It was three o’clock in the morning. Along a deserted pavement of Riverside Drive strode briskly a young man whose square-set shoulders and erect poise suggested a military training. His coat, thrown carelessly open to the cold night wind, displayed an expanse of white indicative of evening dress. As he walked his heels clicked sharply on the concrete with the forceful firm tread of the type which does things quickly and decisively. The intense stillness of the early morning hours carried the sound in little staccato beats that could be heard blocks away. A few yards behind him, moving furtively and noiselessly, almost as if he had been shod with rubber, crept another figure, that of a stocky, broad-shouldered man, who despite his bulk and weight moved silently and swiftly through the night, a soft brown hat drawn low over his eyes as if he desired to avoid recognition.

All at once the man ahead paused suddenly and stood looking out over the river. Between the Drive and the distance-dimmed lights of the Jersey shore there rose like great silhouettes the grim figures of several huge steel-clad battleships, their fighting-tops lost in the shadows of the opposite hills. Beside them, obscure, with no lights visible, lay the great transports that in a few hours, or in a few days—who knew—they would be convoying with their precious cargo of fighting men across the war-perilled Atlantic.

It was on the forward deck of one of these great battleships that the eyes of the man ahead were riveted. His shadower, evidently much concerned in his actions, crept slowly and stealthily forward, approaching nearer and still nearer without being observed.

A dim light became visible on the warship’s deck and then vanished. Still the man stood there watching, a puzzled, anxious look coming into his face. Quickly the light reappeared—two flashes, a pause, two flashes, a pause, and then a single flash. It was such a light as might have been made by a pocket torch, a feeble ray barely strong enough to carry to the adjacent shore, a light that if it had been flashed from some sheltered nook by the boat davits might not even have attracted the attention of the officer on the bridge nor of the ship’s watchmen. Manifestly it was a signal intended for the eyes of some one on shore.

A muttered imprecation escaped the lips of the watcher on the Drive. He stood there, straining his eyes toward the ship as if expecting a following signal, then he turned and gazed aloft at the windows of the apartment houses lining the driveway to see if some answering signal flashed back.

And in the shadow of the buildings, hardly ten feet away but half sheltered by a doorway, stood his sinister pursuer, motionless but alert.

For perhaps a quarter of an hour they held their positions. At last the man who was being followed shrugged his shoulders impatiently and set off again down the Drive, from time to time turning his head to watch the spot from which the signal had been flashed. Behind him, as doggedly as ever and now a little closer, crept the man with the hat over his eyes.

Regardless of the lateness of the hour, at a third-floor window of one of the great apartment houses lining the Drive sat a young girl in her nightrobe, with her two great black braids flung forward over her shoulders, about which she had placed for warmth’s sake a quilted negligee. Jane Strong was far too excited to sleep. An hour before she had come in from a wonderful party. The music still was playing mad tunes in her ears. The excitement, the coffee, the spirited tilts at arms with her many dancing partners had set her brain on fire. Sleep seemed impossible as yet.

Looking out at the river—a favorite occupation of hers—the sight of the warships looming up through the darkness reminded her once more that nearly all of the men with whom she had been dancing had been in uniform, bringing into prominence in the jumble of ideas in her over-stimulated brain, almost as a new discovery, the fact that her country was really engaged in war, that the men, the very men whom she knew best, were most of them fighting, or soon going to fight in a foreign land. Suddenly she found herself vaguely wishing that there was something she might do, something for the war, something to help. Would it not be splendid, she thought, to go to France as a Red Cross nurse, to be over there in the middle of things, where something exciting was forever going on. Life—the only life she knew about, existence as the petted daughter of well-to-do parents in a big city—had, ever since the war had begun, seemed strangely flat and uninteresting. Parties, to be sure, were fun but hardly any one was giving parties this year. The Stantons had entertained only because their lieutenant son was going abroad soon, and they wished him to have a pleasant memory to carry with him. Most of the interesting men she knew already were gone, and now Jack Stanton was going. How she wished she could find some way of getting into the war herself.

The sound of approaching footsteps caught her ear. Wondering who was abroad at that hour of the night she pushed up the window softly and looked out. In the distance she saw a man approaching, striding briskly toward her. As she stood idly watching him and wondering about him, suddenly she caught her breath. She had sighted the other figure behind, the man creeping stealthily after him. Nearer and nearer they came. In tense expectation she waited, sensing some unusual development. They had reached her block now. Almost directly under her window the man in advance paused to light a cigarette. His shadow paused, too, but some incautious movement on his part must have betrayed him.

Match in hand, the man in advance stood stock-still, his whole figure taut, poised, alert, in an attitude of listening. All at once he wheeled about, discovering the man close behind him. He sprang at once for his pursuer. The latter took to his heels, dashing around the corner, the man whom he had been following now hot at his heels.

All trembling with nervous excitement Jane leaned out the window to listen and watch. She could hear the running feet of both men just around the corner. What was happening? The running feet came to an abrupt stop. There was a half-smothered cry, a sharp thud, like a body striking the pavement, and then came silence. Puzzled, vaguely alarmed, a hundred questions came pouring into her brain and lingered there disturbingly. Why had one of these men been shadowing the other? Why had the pursuer suddenly become the pursued? Why had the running footsteps come to such an abrupt stop? What was the noise she had heard? What was happening around the corner? Her fears rapidly growing, she was on the point of arousing her family. But what excuse should she give? What could she tell them? After all she had merely seen two men run up the side street. More than likely they would only laugh at her, and she did not like being laughed at. Besides, Dad was always cross when suddenly awakened. Undecided what to do she stood at the window, peering into the night.

Five minutes, ten minutes she stood there in tremulous perplexity. A sense of impending tragedy seemed to have laid hold of her. A black horror seized her and held her at the window. Something terrible, something tragic, she was sure must have happened. Mustering up her strength and trying to calm her fears she was about to put down the window when she heard footsteps once more approaching. Straining her ears to listen she discovered the sound was that of the steps of a man—one man—approaching from around the corner. As she watched he turned into the Drive and came on toward her. She shrank back a little, fearful of being seen even though her room was in darkness. It was the first man. She recognized him at once by his top-hat and his evening clothes. He was walking even more briskly than before, almost running. There was no sign anywhere of the shorter thick-set man who had been following him. Something in the appearance of the figure in the street below struck her all at once as vaguely familiar. She wondered if it could be any one she knew.

Presently he came directly opposite the light on the other side of the Drive so that it shone for an instant full on his face. Jane looked and shuddered. Never in all her life had she seen any man’s countenance so convulsed, not with pain, but with a soul-terrifying expression of hate, of virulent, murderous hate.

Distorted though the man’s face was with such bitter frightfulness, she recognized him, not as any one she knew, but merely as one of the tenants in the same apartment building.

“It’s one of the people next door,” she said to herself and in verification of her identification, as he approached the building, the young man cast a swift glance over his shoulder, and then, as if satisfied that he was unobserved, dashed hurriedly in at the entrance.

Jane, more than ever wrought up with fear and dread of she knew not what, sprang hastily into bed and drew the covers about her shoulders. As yet she did not lie down but shiveringly waited. Presently she heard the elevator stop. She heard the key opening the door of the next apartment. In a few minutes she heard the man moving about his bedroom, separated from her own room by a mere six inches of plaster and paper, or whatever it is that apartment-house walls are made of.

What could have happened? She was certain that something terrible had occurred in which the young man next door had played a tragic, perhaps even a criminal part. She tried in vain to conjecture what circumstance could have been responsible for the look of hatred she had seen on his face. She wondered what had been the fate of the man who had been following him. Had they quarrelled and fought? What could have been the subject of their quarrel?

She tried to summarize what she knew about the people next door, and was amazed to discover how little she had to draw upon. As in most New York apartment houses so in Jane’s home all the tenants were utter strangers to each other, one family not even knowing the names of any of the others. Occasionally, to be sure, one rather resentfully rode up or down in the elevator with some of the other tenants but always without noticing or speaking to them. Jane’s family had been living in the building for five years, and of the twenty other families they knew the names of only two, having learned them by accident rather than intention. About the people next door Jane now discovered that she really knew nothing at all. There was a man with a gray beard who never took off his hat in the elevator, and there was the handsome young chap whom she had just seen entering. But what their names were, or their business, or how long they had lived there, or whether they were father and son, what servants they kept, or whether either or both of them was married—these were questions she could have answered as readily as if they had been living in Dallas, Texas, or Seattle, Washington, as in the next apartment. Quickly she found that she really knew nothing at all about them except—she could not recall that any one had told her or how she had got the impression—she was almost certain they were some sort of foreigners.

Just when it was that her troubled thoughts were succeeded by even more troubled dreams she was not aware, but it was noon the next day when she was awakened by the maid bringing in her breakfast tray.

“Terrible, Miss Jane, wasn’t it,” said the servant, “about that suicide last night, almost under our noses, you might say.”

“Suicide!” cried the girl, at once wide-awake and interested “What suicide?”

“A man was found dead in the side street right by our building with a revolver in his hand.”

“What sort of a looking man was he?”

“I didn’t see him,” said the maid, almost regretfully. “He was taken away before I was up. Cook tells me it was the milkman found him and notified the police.”

“Who was he?”

“Nobody round here knows a thing about him. He shot himself through the heart and us sleeping here an’ not knowing anything at all about it.”

“But didn’t any one know who he was?”

“Never a soul. The superintendents from all the buildings round took a look at the body, but none of them knew him. It wasn’t anybody that lived around here. There’s a piece in the afternoon papers about it.”

“Get me a paper at once,” directed the girl.

Eagerly she read the paragraph the maid pointed out. It really told very little. The body of a plainly dressed man had been found on the sidewalk. There was a revolver in his hand with one cartridge discharged, and the bullet had penetrated his heart. He had been a short stalky man and had worn a brown soft hat. There was nothing about his clothing to identify him, even the marks where his suit had been purchased having been removed. He had not been identified. The police and the coroner were satisfied that it was a case of suicide.

Suicide!

Jane, reading and rereading the paragraph, recalled the unusual occurrence she had witnessed the night before. Vividly there stood out before her the strange panorama she had seen, the tall young man in evening clothes, and the short stalky man with the soft hat who had followed him. The two of them had run around the corner. Only one of them had come back. Unforgettably there was imprinted in her memory the satanic expression on the young man’s face as he had hastened into the house. No wonder he had cast such an anxious glance behind him as he entered.

Suicide!

Jane was certain that it was no suicide. She remembered the curious thud she had heard from around the corner, like a body falling to the pavement. She recalled that it must have been at least ten minutes before the other man reappeared, time enough to have placed the revolver in the dead man’s hand, time enough even to have removed all possible means of identification from the man’s clothing.

More than likely, she alone in all the world—knew who the murderer was.

It was not suicide, Jane felt certain. It was murder! Slowly but oppressingly, overwhelmingly, it dawned on her not only that in all probability a murder had been committed, but also that she—more than likely, she alone in all the world—knew who the murderer was, who it must have been—the young man next door.

CHAPTER II THE ADDRESS ON THE CARD

Impatiently Jane looked at her wrist watch. It lacked an hour of the time when she was to meet her mother at the Ritz for tea. Her nerves still all ajangle from excitement and worry over the morning’s tragedy, and her own accidental secret knowledge of certain aspects of the case had made it wholly impossible for her to do anything that day with even simulated interest.

She had been debating with herself whether or not to confide to her mother the story of the tragic tableau of which she had been an accidental witness, when Mrs. Strong had dashed into her bedroom to give her a hurried peck on the cheek and to say that she was off to luncheon and the matinée with Mrs. Starrett.

“You’re not looking well to-day, dear,” her mother had said. “Stay in bed and rest and join us for tea if you like.”

Before she had opportunity to tell what she had seen, her mother was gone, but Jane had found it impossible to obey her well-meant injunction. She rose and dressed, her mind busy all the while with the problem of what her duty was. As she donned her clothing she paused from time to time to listen for sounds from the next apartment.

What was her neighbor doing now? Had he read of the discovery of the man’s body in the street? Perhaps he had fled already? Not a sound was to be heard there. He did not look in the least like what Jane imagined a murderer would, yet certainly the circumstances pointed all too plainly to his guilt. She had seen two men dash around the corner, one in pursuit of the other. One of them had come back alone. Not long afterward a body—the body of the other man—had been found with a bullet in his heart. It must have been a murder.

What ought she to do about it? Was it her duty to tell her mother and Dad about what she had seen? Mother, she knew, would be horrified and would caution her to say nothing to any one, but Dad was different. He had strict ideas about right and justice. He would insist on hearing every word she had to tell. More than likely he would decide that it was her duty to give the information to the authorities. Her face blanched at the thought. She could not do that. She pictured to herself the notoriety that would necessarily ensue. She saw herself being hounded by reporters, she imagined her picture in the papers, she heard herself branded as “the witness in that murder case,” she depicted herself being questioned by detectives and badgered by lawyers.

No, she decided, it would be best for her never to tell a soul, not even her parents. In persistent silence lay her safest course. After all she had not witnessed the commission of the crime. She was not even sure that the man found dead had been one of the two she had watched from her window. If she saw the body she would not be able to identify it. She was not even certain in her own mind that the man next door had done the shooting, however suspicious his actions may have appeared to her. Besides, he did not look in the least like a murderer. He was too well-dressed.

In an effort to put the whole thing out of her mind she tried to read, but was unable to keep her thoughts from wandering. She sat down at the piano, but music failed to interest or soothe her. She mussed over some unanswered notes in her desk but could not summon up enough concentration of mind to answer them. Restless and fidgety, unable to keep her thoughts from the unusual occurrences that had disturbed her ordinarily too peaceful life, she decided to take a walk until it was time to keep her appointment. Something—force of habit probably—led her to the shopping district. With still half an hour to kill, she went into a little specialty shop to examine some knitting bags displayed in the window.

“Why don’t you knit as all the other girls are doing?” was her father’s constant suggestion every time she asserted her desire to be doing something in the war.

“There’s no thrill in knitting,” she would answer. “Fix it, Dad, so that I can go to France as a Red Cross nurse or as an ambulance driver, won’t you? I want some excitement.”

Always he had refused to consent to her going, insisting that France in wartime was no place for an untrained girl.

“If I can’t go myself, I certainly am not going to send any knitting,” she would spiritedly answer, but several times recently the sight of such charming looking knitting bags had tempted her into almost breaking her resolution.

Inside the shop she found nothing that appealed to her, and contented herself with buying some toilet articles. As she made her purchases she noticed, almost subconsciously, a man standing near, talking with one of the shopgirls—a middle-aged man with a dark mustache.

“The address, please,” said the girl, who had been waiting on her.

“Miss Strong,” she answered, giving the number of the apartment house on Riverside Drive.

She recalled afterward that as she mentioned the number the man standing there had turned and looked sharply at her, but she thought nothing of it. Her father’s name was well known and he had many acquaintances in the city. More than likely, she supposed, this man was some friend of her father who had recognized the name.

She lingered a few moments at some of the other counters, aimlessly inspecting their offerings, and at last, with ten minutes left to reach the Ritz, emerged from the store. She was amazed to see the man who had been inside now standing near the entrance, and something within warned her that he had been waiting to speak to her. As she attempted to pass him quickly, he stepped in front of her, blocking her path, but raising his hat deferentially.

“I beg your pardon, Miss Strong,” he said, “may I have a word with you?”

Compelled to halt, she looked at him both appraisingly and resentfully. There was nothing offensive nor flirtatious in his manner, and he seemed far too respectably dressed to be a beggar. He was almost old enough to be her father, and besides there was about him an indefinable air of authority that commanded her attention. She decided that, unusual as his request appeared, she would hear what he had to say.

“What is it?” she asked, trying to assume an air of hauteur but without being able wholly to mask her curiosity.

“You are an American, aren’t you?” he asked abruptly.

“Of course.”

“A good American?”

“I hope so.” She decided now that he must be one of the members of some Red Cross fund “drive,” or perhaps an overenthusiastic salesman for government bonds. “But I don’t quite understand what it is that you wish.”

“I can’t explain,” said her questioner, “but if you really are a good American and you’d like to do your country a great service—an important service—go at once to the address on this card.”

She took the slip of white pasteboard handed her. On it was written in pencil “Room 708.” The building was a skyscraper down-town.

“What is it?” she asked half indignantly, “a new scheme to sell bonds?”

“No, no, Miss Strong,” he cried, “it is nothing like that. It is a great opportunity to do an important service for America.”

“How did you know my name?”

“I heard you give it to the clerk just now.”

“And why,” she inquired with what she intended to be withering sarcasm, “have I been selected so suddenly for this important work?”

“I heard the address you gave, that’s why,” he answered. “That’s what makes it so important that you should go to that number at once. Ask for Mr. Fleck.”

“I can’t go,” she temporized. “I am on my way now to meet my mother at the Ritz.”

“Go to-morrow, then,” he insisted. “I’ll see Mr. Fleck meanwhile and tell him about you.”

Puzzled at the man’s unusual and wholly preposterous request, yet in spite of herself impressed by his evident sincerity, Jane turned the card nervously in her hand and discovered some small characters on the back; “K-15” they read.

“What do those figures mean?” she asked.

“I can’t tell you that. Mr. Fleck will explain everything. Promise me you will go to see him.”

“Who are you?”

“I can’t tell you that, yet.”

“Who, then, is Mr. Fleck?”

“He will explain that to you.”

“What has my address to do with it? I can’t understand yet why you make this preposterous request of me.”

“I tell you I can’t explain it to you, not yet,” the man replied, “but it’s because you live where you do you must go to see Mr. Fleck. It’s about a matter of the highest importance to your government. It is more important than life and death.”

His last words startled her. They brought to her mind afresh the mysterious occurrence she had witnessed the night before and the equally mysterious death near her home. Had this man’s odd request any connection, she wondered, with what had happened there? The lure of the unknown, the opportunity for adventure, called to her, though prudence bade her be cautious.

“I’ll ask my mother,” she temporized.

“Don’t,” cried the man. “You must keep your visit to Mr. Fleck a secret from everybody. You mustn’t breathe a word about it even to your father and mother. Take my word for it, Miss Strong, that what I am asking you to do is right. I’ve two daughters of my own. The thing I’m urging you to do I’d be proud and honored to have either of them do if they could. There is no one else in the world but you that can do this particular thing. A word to a single living soul and you’ll end your usefulness. You must not even tell any one you have talked with me. See Mr. Fleck. He’ll explain everything to you. Promise me you’ll see him.”

“I promise,” Jane found herself saying, even against her better judgment, won over by the man’s insistence.

“Good. I knew you would,” said her mysterious questioner, turning on his heel and vanishing speedily as if afraid to give her an opportunity of reconsidering.

Puzzled beyond measure not only at the man’s strange conduct but even more at her own compliance with his request, Jane made her way slowly and thoughtfully to the Ritz, where she found her mother and Mrs. Starrett had already arrived.

As they sipped their tea the two elder women chatted complacently about the matinée, about their acquaintances, about other women in the tea-room and the gowns they had on, about bridge hands—the usual small talk of afternoon tea.

To Jane, oppressed with her two secrets, all at once their conversation seemed the dreariest piffle. Great things were happening everywhere in the world, nations at war, men fighting and dying in the trenches of horror for the sake of an ideal, kings were being overthrown, dynasties tottering, boundaries of nations vanishing. Women, she realized, too, more than ever in history, were taking an active and important part in world affairs. In the lands of battle they were nursing the wounded, driving ambulances, helping to rehabilitate wrecked villages. In the lands where peace still reigned they were voting, speech-making, holding jobs, running offices, many of them were uniting to aid in movements for civic improvement, for better children, for the improvement of the whole human race.

And here they were—here she was, idling uselessly at the Ritz as she had done yesterday, last week, last month—forever, it seemed to her. The vague protest that for some time had been growing within her against the senselessness and futility of her manner of existence crystallized itself now into a determination no longer to submit to it. Courageously she was resolving that she would take the first opportunity to escape from this boresome routine of pleasure-seeking. She was wondering if the request that had been so unexpectedly made of her would prove to be her way out from her prison of desuetude.

The talk of the two women with her drifted aimlessly on. Seldom was she included in it, save when her mother, nodding to some one she knew, would turn to say:

“Daughter, there is Mrs. Jones-Lloyd.”

What did she care about Mrs. Jones-Lloyd? What did she care about any of the people about them, aimless, pleasure-hunting drifters like themselves. Left to her own devices for mental activity her thoughts kept recurring to the surprising adventure she had had a few minutes before. Thoughtfully she pondered over the mysterious message that had been given to her. The man had said that it was a wonderful opportunity for her to do her country a great service. She wondered why he had been so secretive about it. She decided that she would investigate further and made up her mind to carry out his instructions. What harm could befall her in visiting an office building in the business district? At least it would be something to do, something new, something different, something surely exciting and, perhaps, something useful.

It would be better, she decided, for the present at least, to keep her intentions entirely to herself. Any hint of her plans to her mother would surely result in permission being refused. The man certainly had seemed sincere, honest, and perfectly respectable, even if he was not of the sort one would ask to dinner. She made up her mind to go down-town to the address given the very first thing to-morrow morning. If anything should happen to her, she felt that she could always reach her father. His office was in the next block.

The problem of making the mysterious journey without her mother’s knowledge bothered her not at all. As in the case of most apartment-house families, she and her mother really saw very little of each other, especially since she had become a “young lady.” Mrs. Strong went constantly to lectures, to luncheons, to bridge parties, to matinées with her own particular friends. Jane’s engagements were with another set entirely, school friends most of them, whose parents and hers hardly knew each other. Both she and her mother habitually breakfasted in bed, generally at different hours, and seldom lunched together. At dinner, when Mr. Strong was present, there were no intimacies between mother and daughter. The only times they really saw each other for protracted periods were when they happened to go shopping, or go to the dressmaker’s together, and then the subject always uppermost in the minds of both of them was the all-important and absorbing topic of clothes. Occasionally, Jane poured at one of her mother’s more formal functions, but for the most part the time of each was taken up in a mad, senseless hunt for amusement.

Suddenly every thought was driven from Jane’s head. Her face went white, and with difficulty she managed to suppress an alarmed cry.

“What is it, daughter?” asked her mother, noting her perturbation. “Are you feeling ill?”

“A touch of neuralgia,” she managed to answer.

“Too many late hours,” warned Mrs. Starrett reprovingly.

“I’m afraid so,” said Mrs. Strong. “As soon as I’ve paid my check we’ll go.”

“I’m perfectly all right now,” said Jane, controlling herself with effort, though her face was still white.

The danger that she had feared had passed for the present at least. Glancing toward the entrance a moment before she had been terrified to see entering the black-mustached man who had accosted her a few moments before. Her one thought now had been that he had followed her here, and in a panic she was wondering how she should make explanations if he came up to their table and spoke. To her great relief he gave no intimation of having seen her, but settled himself into a chair near the door where he was half hidden from her by a great palm. Furtively she watched him, trying to divine his intention in having followed her there. Respectable enough though he was in appearance and garb, he did not seem in the least like the sort of man likely to be found at tea-time in an exclusive hotel. As she studied him she soon saw that his attention seemed to be riveted on some one sitting at the other side of the room. Wonderingly she let her eyes follow his, and once more it was with difficulty that she suppressed an excited gasp.

There, across the room, calmly sipping some coffee, was the handsome young man from the next apartment—the man whom she had felt sure, or at least almost sure, was a murderer, about whom she had been wondering all day long, picturing him as a hunted criminal fleeing from the law. Chatting interestedly with him was another man, a young man in the uniform of a lieutenant in the navy.

What did it all mean? Why was the black-mustached man watching them so intently? Her eyes turned back to him. He was still sitting there, leaning forward a little, his brows in a pucker of concentration, his eyes still fixed on the pair opposite. It looked almost as if he was trying to read their lips and tell what they were talking about.

Jane thrilled with excitement. The black-mustached man, she decided, must be a detective. She recalled that he had said to her it was because she lived at the address she did that she was available for the mission for which he wanted her. Did he, she wondered, know about the mysterious death in the street outside their apartment house? Was that the reason he was spying on her neighbor? But what could be his motive in seeking to involve her in the matter?

Unable to find satisfactory answers to her questions she gave herself up interestedly to studying the faces of the two young men across the room. Neither of them, she decided, could be much more than thirty. The face that only a few hours before she had seen utterly convulsed with bitter hate, now placid and smiling, was really an attractive one, not in the least like a murderer’s. Frank, alert blue eyes looked out from under an intellectual forehead. A small military mustache lent emphasis to a clean-shaven, forceful jaw. His flaxen hair was neatly trimmed. His linen and clothing were immaculate, and the hand that curved around his cup had long, tapering, well-manicured fingers. The cut of his clothing, his manners, everything about him seemed American, yet there was an indefinable something in his appearance that suggested foreign birth or parentage, probably either Swedish or German. The man with him was smaller and slighter. Despite the air of importance his uniform gave him, it was palpable that he was the less forceful of the two, his handsome face, it seemed to Jane, betraying weakness of character and a fondness for the good things of life.

“Come, daughter,” said Mrs. Strong, rising, “we must be going.”

So intent was Jane on her study of the two men that her mother had to speak twice to her.

“Yes, mother,” she answered obediently, rising hastily as the hint of annoyance in her mother’s repeated remark brought her to a realization of having been addressed.

Letting her mother and Mrs. Starrett precede her in the doorway she paused to look back at the scene that had interested her so strongly. What could it mean? What was going on? How was she involved in it?

Her glance moved quickly from the watcher to the watched. The blond young man caught her eye. Amazedly, it seemed to her, he stopped right in the middle of what he was saying and sat there, his gaze fixed full on her. She let her eyes fall, abashed, and turned to hasten after her mother, but not so quickly did she turn but that she observed he had hastily seized his cup and appeared to be drinking to her, not so much impudently as admiringly.

CHAPTER III “MR. FLECK”

Twice after the elevator had deposited her on the floor Jane had approached the door of Room 708, and twice she had walked timorously past it to the end of the hall, trying to muster up courage to enter. A visit to a man’s office in the business district was a novelty for her. On the few previous excursions of the sort she had made she always had been accompanied by one of her parents. She found herself wishing now that she had taken her father into her confidence and had asked him to go with her. Making shopping her excuse she had come down-town with Mr. Strong but had gotten off at Astor Place, and waited over for another train.

In her hand she held the card given to her by the black-mustached man the afternoon before. As she studied it now her curiosity came to the rescue of her fast-oozing courage. She must find out what it all meant, whatever the risk or peril that might confront her. Boldly she returned to Room 708 and opened the door. An office boy seated at a desk looked up inquiringly.

“Is Mr. Fleck in?” she inquired timidly.

“Who wishes to see him?”

“Just say there’s a lady wishes to speak to him,” she faltered, hesitating to give her name.

“Are you Miss Strong?” asked the boy abruptly, “because if you are, he’s expecting you.”

She nodded, and the boy, jumping up, escorted her into an inner room. As she entered nervously an alert-looking man, with graying hair and mustache, rose courteously to greet her. In the quick glance she gave at her surroundings she was conscious only of the great mahogany desk at which he sat and behind it some filing cabinets and a huge safe, the outer doors of which stood open.

“Sit down, won’t you, Miss Strong,” he said, placing a chair for her.

His manner and his cultured tone, everything about him, reassured her at once. They conveyed to her that he was what she would have termed “a gentleman,” and with a little sigh of relief she seated herself.

“I’m afraid,” said Mr. Fleck, smiling, “that Carter’s method of approaching you must have alarmed you.”

“Carter—Oh, the black-mustached man.”

“Yes, that describes him. You see, he did not wish to act definitely without consulting his chief, yet the unexpected opportunity seemed far too vital not to be utilized. He did not explain, did he, what it was we wanted of you?”

“Indeed he didn’t,” said Jane, now wholly herself. “He was most mysterious about it.”

Mr. Fleck smiled amusedly.

“Carter has been an agent so long that being mysterious is second nature to him.”

“An agent—I don’t understand.”

“A Department agent,” explained Mr. Fleck, adding, “engaged in secret service work for the government.”

“Oh!”

Jane’s exclamation was not so much of surprise as of delighted realization, and the satisfaction expressed in her face was by no means lost on Mr. Fleck.

“Would you object,” he asked, moving his chair a little closer to hers, “if, before I explain why you are here, I ask you a few questions—very personal questions?”

“Certainly not,” said Jane.

“You are American-born, of course?”

“Oh, yes.”

“And your parents?”

“American for ten or twelve generations.”

“How long have you lived in that apartment house on Riverside Drive?”

“For about five years.”

“Do you know any of the other tenants in the house?”

“No—that is, none personally.”

“Is your time fully occupied?”

“No, indeed it isn’t, I’ve nothing to do at all, nothing except to try to amuse myself.”

“Good,” said Mr. Fleck. “Now would you be willing to help in some secret work for the United States Government, some work of the very highest importance?”

“Would I?” cried Jane, her eyes shining. “Gladly! Just try me.”

“Don’t answer too quickly,” warned Mr. Fleck. “Remember, it will be real work, serious work, not always pleasant, sometimes possibly a little perilous. Remember, too, it must be done with absolute secrecy. You must not let even your parents know that you are working with us. You must pledge yourself to breathe no word of what you are doing or are asked to do to a living soul. Everything that we may tell you is to be buried forever from everybody. No one is to be trusted. The minute one other person knows your secret it will no longer be a secret. Can we depend upon you?”

“You may absolutely depend on me,” said Jane slowly and soberly. “I give you my word. I have been eager for ever so long to do something to help, to really help. My father is doing all he can to aid the government. He’s on the Shipping Board.”

Mr. Fleck nodded. Evidently he was aware of it already.

“My brother, my only brother,” Jane continued, with a little catch in her throat, “is Over There—somewhere Over There—fighting for his government. If there is anything I can do to help the country he is fighting for, the country he may die for, I pledge you I will do it gladly with my heart, my soul, my body—everything.”

“Thank you,” said Mr. Fleck softly, taking her hand. “I felt sure you were that sort of a girl. Now listen.” He moved his chair still closer to hers, and his voice became almost a whisper. “In the apartment next to you there live two men,—Otto Hoff and his nephew, Fred. They have an old German servant, but we can leave her out of it for the present. The old man is a lace importer. Apparently they are both above suspicion, yet—”

He stopped abruptly.

“You think they are spies—spies for Germany,” questioned Jane excitedly. “They’re Germans, of course?”

“Otto Hoff is German-born, but he has been here for twenty years. Several years ago he took out papers and became an American citizen.”

“And the young man?”

Jane’s tone was vibrant with interest. It must be the man she had seen from her window whom they suspected most.

“He professes to be American-born.”

“Oh,” said the girl, rather disappointedly.

“But,” continued Mr. Fleck, “there’s something queer about it all. He arrived in this country only three days before we went into the war. He had a certificate, properly endorsed, giving his birthplace as Cincinnati. He arrived on a Scandinavian ship. He speaks German as well and as fluently as he speaks English, both without accent.”

“Perhaps he was educated abroad,” suggested Jane, rather amazed at finding herself seeking to defend him.

“He must have been,” said Fleck, “yet I find it hard to believe that Germany at this time is letting any young German-American come home if he’s soldier material—and young Hoff’s appearance certainly suggests military training.”

“It surely does.”

“Unless,” continued Fleck, “there was some special object in sending him here.”

“You think,” said Jane slowly, “they sent him here—to this country—as a spy.”

“In our business we dare not think. We cannot merely conjecture. We must prove,” said Mr. Fleck. “Maybe the Hoffs are O.K. I do not know. Nobody knows yet. Let me tell you some of the circumstances. This much we do know. Von Bernstorff is gone. Von Papen is gone. Scores of active German sympathizers and propagandists have been rounded up and interned or imprisoned, yet, in spite of all we have done, their work goes on. A vast secret organization, well supplied with funds, is constantly at work in this country, trying to cripple our armies, trying to destroy our munition plants, trying to corrupt our citizens, trying to disrupt our Congress. Every move the United States makes is watched. As you probably know, every day now large numbers of American troops are embarking in transports in the Hudson.”

“Yes,” said Jane, “you can see them from our windows.”

“Now then,” said Mr. Fleck, lowering his voice impressively, “here is the fact. Some one somewhere on Riverside Drive is keeping close and constant tab on the warships and transports there in the river. We have managed recently to intercept and decipher some code messages. These messages told not only when the transports sailed but how many troops were on each and how strong their convoy was. Where these messages originate we have not yet learned. We are practically certain that some one in our own navy, some black-hearted traitor wearing an officer’s uniform—perhaps several of them—is in communication with some one on shore, betraying our government’s most vital secrets.”

“I can’t believe it,” cried Jane, “our own American officers traitors!”

“Undoubtedly some of them are,” said Mr. Fleck regretfully. “The German efficiency, for years looking forward to this war, carefully built up a far-reaching spy system. Years ago, long before the war was thought of—or at least before we in this country thought of it—many secret agents of Wilhelmstrasse were deliberately planted here. Many of them have been residents here for years, masking their real occupation by engaging in business, utilizing their time as they waited for the war to come by gathering for Germany all of our trade and commercial secrets. Some of these spies have even become naturalized, and they and their sons pass for good American citizens. In some cases they have even Americanized their names. Insidiously and persistently they have worked their way into places, sometimes into high places in our chemical plants, our steel factories, yes, even into high places in our army and navy and into governmental positions where they can gather information first-hand. In no other country has it been so easy for them, because of this one fact: so large a proportion of Uncle Sam’s population is of German birth or parentage. Why here in New York City alone there are more than three-quarters of a million persons, either German-born themselves or born of German parents. Many of them, the vast majority of them, probably, are loyal to America, but think how the plenitude of German names makes it easy for spies to get into our army and navy. Besides that, they employ evil men of other nationalities as spies, the criminal riffraff,—Danes, Swedes, Spaniards, Italians, Swiss and even South Americans,—all of whom are free to go and come as they choose in this country.”

“I never realized before,” said Jane, “how many Germans there were all about us.”

“In an effort to locate this particular band of naval spies,” continued Mr. Fleck, “we have combed the apartment houses and residences along the Drive. Three places in particular are under suspicion. The apartment of the Hoffs is one of these places. They moved in there thirty days after this country went to war. Ordinarily, where the occupants of an apartment are under suspicion, we take the superintendent of the building partly into our confidence and plant operatives in the house, or else we hire an apartment in the same building. In this case neither course is practicable. The superintendent of your building is a German-American and we dare not trust him, and there is no vacant apartment that we can rent. We have been watching the Hoffs from the outside as best we could. Carter, who has had charge of the shadowing, accidentally happened to overhear you give your address. He had procured a list of the tenants and remembered the location of your apartment. It struck him at once that you would be a valuable ally if you would consent to work with us.”

“What is it that you wish me to do?” asked Jane wonderingly. “You’ll have to tell me how to go about it.”

“All a good detective needs,” said Mr. Fleck, “is, let us say, three things—observation, addition and common sense. You must observe everything closely, be able to put two and two together and use your common sense. Do you know the Hoffs by sight?”

“Only by sight.”

“They live in the next apartment on your floor, do they not?”

“Yes. Young Mr. Hoff’s bedroom is the room next to mine.”

“Good,” cried Mr. Fleck. “Can you hear anything from the next apartment, any conversations?”

“No, only muffled sounds.”

“The windows overlook the river and the transports, do they not?”

“Yes, the windows of Mr. Hoff’s bedroom and the room next. Their apartment is a duplicate of ours.”

Mr. Fleck sprang up and crossed to the big safe. Opening an inner drawer he took out a small metal disk and handed it to her. Jane looked at it curiously. It bore no wording save the inscription “K-19.”

“That,” said Mr. Fleck, “is the only thing I can give you in the way of credentials. Keep it somewhere safely concealed about your clothing and never exhibit it except in case of extreme necessity. If ever you are in peril any police officer will recognize it at once and will promptly give you all the assistance possible.”

“But,” protested the girl, “I don’t know yet what I am to do.”

“For the present I am trusting to your resourcefulness to make opportunities to help us. We are watching the house closely from the outside. Carter will identify you to the other operatives. Once a day I will expect you to call me up, not from your home but from a public ’phone. Here is my number. Say ‘this is Miss Jones speaking,’ and I will know who it is. I can communicate with you by note without arousing suspicion?”

“Oh, yes, certainly.”

“If at any time I have to call you on the ’phone, or if any of the other operatives want to communicate with you the password will be ‘I am speaking for Miss Jones.’”

“Isn’t that exciting—a secret password,” cried Jane enthusiastically.

“If you can manage it without compromising yourself too seriously, I wish you would make the young man’s acquaintance.”

“That will be simple,” said Jane, remembering the admiring way in which he had raised his cup in her direction as she left the hotel.

“If possible find out who their visitors are in the apartment and keep your eyes open for any sort of signalling to the transports. If ever there is an opportunity to get hold of notes or mail delivered to either of them, don’t hesitate to steam it open and copy it.”

“Must I?” said Jane. “That hardly seems right or fair.”

“Of course it’s right,” cried Mr. Fleck warmly. “Think of the lives of our soldiers that are at stake. The devilish ingenuity of these German spies must be thwarted at all costs. They seem to be able to discover every detail of our plans. Only two days ago one of our transports was thoroughly inspected from stem to stern. Two hours later twenty-six hundred soldiers were put aboard her on their way to France. Just by accident, as they were about to sail, a time-bomb was discovered in the coal bunkers, a bomb that would have sent them all to kingdom come.”

“How terrible!”

“Somebody aboard is a traitor. Somebody knew when that inspection was made. Somebody put that bomb in place afterward. That shows you the kind of enemies we are fighting.”

Jane shuddered. She was thinking of the sailing of another transport, the one that had carried her brother to France.

“Anything seems right after that,” she said simply.

“Yes,” said Mr. Fleck, “there is only one effective way to fight those spying devils. We must stop at nothing. They stop at nothing—not even murder—to gain their ends.”

“I know that,” said Jane hastily. “I saw something myself you ought to know about.”

As briefly as she could she described the scene she had witnessed in the early morning hours from her bedroom window, the man following the younger Hoff, Hoff’s discovery and pursuit of him around the corner and of his return alone.

“And in the morning,” she concluded, “they found a man’s body in the side street. He had a bullet through his heart. There was a revolver in his hand. The newspapers said that the police and the coroner were satisfied that it was a suicide. I caught a glimpse of Mr. Hoff’s face when he came back from around that corner. It was all convulsed with hate, the most terrible expression I ever saw. I’m almost certain he murdered that man. I’m sure it wasn’t a suicide.”

“I’m sure, too, that it was no suicide,” said Mr. Fleck gravely. “The man who was found there was one of my men, K-19, the man whose badge I have just given you. He had been detailed to shadow the Hoffs.”

CHAPTER IV THE CLUE IN THE BOOK

Subway passengers sitting opposite Jane Strong as she rode up-town from Mr. Fleck’s office, if they observed her at all—and most of them did—saw only a slim, good-looking young girl, dressed in a chic tailormade suit, crowned with a dashing Paris hat tilted at the proper angle to display best the sheen of her black, black hair, which after the prevailing fashion was pulled forward becomingly over her ears. Outwardly Jane was unchanged, but within her nerves were all atingle at the thought of the tremendous and fascinating responsibility so unexpectedly thrust upon her. Her mind, too, was aflame with patriotic ardor, but coupled with these new sensations was a persisting sense of dread, an intangible, unforgettable feeling of horror that kept cropping up every time her fingers touched the little metal disk in her purse.

The man who had carried it yesterday, the other “K-19” who had undertaken to shadow those people next door, now lay dead with a bullet through his heart. Was there, she wondered, a similar peril confronting her? Would her life be in danger, too? Was that the reason Mr. Fleck had told her of her predecessor’s fate—to warn her how desperate were the men against whom she was to match her wits? Yet no sense of fear that projected itself into her busy brain as she cogitated over the task before her held her back. If anything she was rather thrilled at the prospect of meeting actual danger. What bothered her most was how she could best go about aiding Mr. Fleck and his men in their work.

Her opportunity came far more quickly than she had anticipated. She had gotten off the train at the 96th Street station, purposing to walk the twenty odd blocks to her home as she pondered over the work that lay ahead of her. Busy with a horde of struggling new thoughts she proceeded along Broadway, for once in her life unheeding the rich gowns and feminine dainties so alluringly displayed in the shop windows. Suddenly she pulled herself together with a start. Directly ahead of her, plodding along in the same direction, was a figure that from behind seemed strangely familiar. She quickened her step until she caught up sufficiently with the man ahead to get a good glimpse of his side face. Nervously she caught her breath. Without any doubt it was the gray Van Dyke beard of old Otto Hoff.

Where was he going? What was he doing? She paused and looked behind her, scanning the pavement on both sides of the street. She was half-hoping that she would discover Carter or some of his men shadowing their quarry, but her hope was vain. There was no one in the block at the moment but herself and Mr. Hoff. If Fleck’s men had been watching his movements, the old man certainly seemed to have eluded them.

What should she do? Vividly there flashed into her mind her chief’s parting words.

“Watch everything,” he had charged her. “Remember everything, report everything. No detail is too unimportant. If you see one of the Hoffs leave the house, don’t merely report to me that the old man or the young man left the house about three o’clock. That won’t do at all. I want to know the exact time. Was it six minutes after three or eleven minutes after three? I must know what direction he went, if he was alone, how long he was absent, where he went, what he did, to whom he talked. Here in my office I take your reports, Carter’s reports, a dozen other reports, and study them together. Things that in themselves seem trifling, unimportant, of no value, coupled with other seemingly unimportant trifles sometimes develop most important evidence.”

To prove his point he had told her of the seemingly innocent wireless message that an operator, listening in, had picked up, at a time when Germans were still permitted to use the wireless station on Long Island for commercial messages to the Fatherland. On the face of it, it was the mere announcement of the death of a relative with a few details. But a little later the same operator caught the same message coming from another part of the country, with the details slightly different, and still later another message of the same purport. Evidently, by comparing the messages, the United States authorities had been able to work out a code.

Remembering this, Jane decided that it was her particular duty just now to follow the old German and note everything he did. For several blocks she trailed along behind him, without arousing any suspicion on his part that he was being followed. He stopped once to light a cigarette, the girl behind him diverting suspicion by hastily turning to a shop window. Again he stopped, this time before the display of viands in the window of a delicatessen store. Thoughtfully Jane noted the number, observing, too, that the name of the proprietor above the door was obviously Teutonic. She was half-expecting to see her quarry turn in here, but he walked on to the middle of the next block, where he entered a stationery store.

Hesitating but a second, to decide on a course of action, she followed him boldly into the store. She felt that she must ascertain just what he was doing in there. As she entered she saw that in the back part of the store was a lending library. Mr. Hoff had gone back to it and was inspecting the books displayed there. Unhesitatingly she, too, approached the book counter.

“Have you ‘Limehouse Nights’?” she asked the attendant, naming the first book that came into her head. She had a copy of the book at home, but that seemed to be the only title she could think of.

“We have several copies,” the girl in charge answered, “but I think they are all out. I’ll look.”

As the clerk examined the shelves, Jane kept up a desultory talk with her, questioning her about various books on the shelves, all the while watching the old German out of the corner of her eye. His back was toward her, and he seemed to be examining various books on the shelves, turning over the pages as if unable to decide what he wanted. Curious as to what his taste in reading was, Jane endeavored to locate each book that he removed from its place, her idea being that she would later try to discover their titles. To her amazement she found that it was invariably the third book in each shelf that he removed and examined—the third from the end. It did not appear to her that he was examining the contents of the pages so much as searching them as if he expected to find something there.

All at once, as she furtively watched from behind him, she heard him give a little pleased grunt and she saw him picking out from between the leaves of the book a fragment of paper, which he held concealed in his hand. Watching closely, Jane saw him thrust this same hand into his trousers pocket, and when he brought it out she was certain that the hand was empty. What did this curious performance mean? What was the little slip of paper he had found in the book? Why had he concealed it in his pocket?

Still keeping her attention riveted on him, she picked up a book to mask her occupation and pretended to be turning its pages. She was glad she had done so, for a minute later old Hoff wheeled suddenly and looked sharply about him. Apparently having his suspicions disarmed by seeing only herself and the clerk there, he turned again to the bookshelves. Jane this time saw him thrust his fingers into his waistcoat pocket and withdraw therefrom,—she was almost certain of it,—a little slip of paper. She saw him remove from the second row of books the fifth from the end, open it quickly and close it again and then restore it to its place. As he did so he turned to leave the store.

“Didn’t you find anything to read to-day, Mr. Hoff?” the clerk asked.

“Nodding,” he answered. “You keep novels, trash, nodding worth while.”

Her nerves aquiver, Jane waited until he was out of the store and then stepped briskly to the place where he had stood. Hastily she pulled forth the fifth book from the end in the second row. Turning its pages she came upon what she had anticipated,—a strip of yellow manila paper,—the paper she was sure she had seen him take from his pocket. Hastily she examined it, expecting to find some message written there. To her chagrin it was just a meaningless jumble of figures in three columns.

534	5	2
331	54	6
544	76	3
49	12	9
540	30	12
390	3	2
519	3	6
327	20	2

		97

Her first thought was to thrust the little scrap of paper in her purse and start again in pursuit of old Hoff, but a sudden light began to dawn on her. This was a cipher message, of course. The old man had left it here for some one to come and get. If she followed Hoff, how was she to discover who the message was for? Puzzled as to what she should do, she borrowed a pencil from the clerk on the pretense of writing a postal and hastily copied the figures, after which she restored the slip to the book in which she had found it.

Glancing about undecidedly, wondering if it would do to take the clerk into her confidence, wishing she had some means of reaching Mr. Fleck and asking his advice, she spied in a drug-store just across the street a telephone booth. She could telephone from there and at the same time keep her eye on the store. Quickly she did so, twisting her head around all the time she was ’phoning to make sure that no one entered opposite.

“Is this Mr. Fleck?” she asked. “This is Miss Jones.”

“So soon?” came back his voice. “What has happened? What is the matter? Have you changed your mind?”

“Not at all,” she answered indignantly. “I’ve discovered something already—a cipher message.”

“What’s that?”

Even over the wire she could sense the eagerness in Mr. Fleck’s tone, and a sense of achievement brought a radiant glow to her cheek.

“I ran into that man—you know whom—”

“The young one?” he interrupted.

“No, the uncle.”

“Yes, yes, go on,” cried Mr. Fleck impatiently.

“I followed him along Broadway after I got off at 96th Street and into a library and stationery store. I watched him fuss over the books there, and I think he got a slip of paper with a message out of one of them.”

“Good,” cried Mr. Fleck, “that is something new. Go on.”

“And then he slipped a paper into a book—”

“Did you notice what book?”

“I don’t know the title. It was the fifth book from the end on the second shelf, and I got the paper and copied it.”

“Splendid. What did the message say?”

“It’s just a lot of figures. I put it back after copying it, and I am in a drug-store across the street where I can watch to see if any one comes to get the message. What shall I do now?”

“Can you remain there fifteen minutes without arousing suspicion?”

“Certainly. I’ll say I am waiting for some one.”

“Good. I’ll get in touch with Carter at once. He’ll tell you what to do when he arrives.”

Impatiently Jane sat there, keeping vigilant watch on the entrance across the street, determined to be able to describe minutely each person that entered. From time to time she surreptitiously studied the postcard on which she had jotted down the mysterious numbers. How utterly meaningless they looked. Surely it would be impossible for any one, even Mr. Fleck, to decipher any message that these figures might convey. It would be impossible unless one had the key. Figures could be made to mean anything at all. She doubted if her discovery could be of much importance after all, yet certainly Mr. Fleck had seemed quite excited about it.

She spied Carter passing in a taxi. Two other men were with him. Her first impulse was to run out in the street and signal to him, but she waited, wondering what she should do. She was glad she had not acted impulsively, for a moment later Carter entered alone, evidently having left the car somewhere around the corner. She expected that he would address her at once, but that was not Carter’s way. He went to the soda counter and ordered something to drink, his eyes all the while studying his surroundings. Presently he pretended to discover her sitting there. To all appearances it might have been an entirely casual meeting of acquaintances.

“Good-morning, Miss Jones,” he said quite cordially, extending his hand. “I’m lucky to have met you, for my daughter gave me a message for you.”

He put just a little stress on the words “my daughter” and Jane understood that he was referring to “Mr. Fleck.”

“Indeed,” she replied, “what is it?”

“She wants you to go down-town at once and meet her at Room 708—you know the building.”

“Aren’t you coming, too?”

“Not right away. I have some errands to do in the neighborhood. I’ve got to buy a book for a birthday present. There’s a library around here somewhere, isn’t there?”

“Just across the street,” said Jane, entering into the spirit of the masked conversation with interest. “I was looking at a fine book over there a few minutes ago. You’ll find it on the second shelf—the fifth book from the end, on the north side of the store.”

“I’ll remember that,” said Carter, repeating, “the fifth book on the second shelf.”

“That’s right,” said Jane, as they left the drug-store together.

“Which way did the old man go?” asked Carter.

“Down Broadway—toward home,” she replied. “I wanted to follow him, but it seemed more important to stay here and watch to see if any one came for the message he left there in the book.”

“You did just right, and the Chief is tickled to death. He wants to see you right away. You have a copy of the message, haven’t you?”

“Yes, do you wish to see it?”

“No, but he does. Has anybody entered the store since you were there?”

“Nobody, that is no one but a couple of girls.”

“What did they look like? Describe them.”

“Why,” Jane faltered, “I did not really notice. I was not looking for girls. I was watching to see that no other men entered the store.”

Carter shook his head.

“You ought to have spotted them, too. You never can tell who the Germans will employ. They have women spies, too,—clever ones.”

“I never thought of their using girls,” protested Jane.

“Humph,” snapped Carter, “ain’t we using you? Ain’t one of our best little operatives right this minute working in a nursegirl’s garb pulling a baby carriage with a baby in it up and down Riverside Drive? Well, it can’t be helped. You’d better beat it down-town to the Chief right away.”

“I’ll take a subway express,” said Jane, feeling somewhat crestfallen at his implied suggestion of failure.

Twenty-five minutes later found her once more in Mr. Fleck’s office. Thrilling with the excitement of it all she told him in detail how she had followed old Hoff and of his peculiar actions in the bookstore.

“And here,” she said, presenting the postcard, “is an exact copy of the cipher message he left there. I copied every figure, in the columns, just as they were set down. I don’t suppose though you’ll be able to make head or tail out of it. I know I can’t.”

“Don’t be too sure of that,” smiled Chief Fleck, as he took the card. “When you get used to codes, most of them identify themselves at the first glance—at least they tell what kind of a code it is. That’s one thing about the Germans that makes their spy work clumsy at times. They are so methodical that they commit everything to writing. Now the most important things I know are right in here”—he tapped his head. “Every once in a while they ransack my rooms, but they never find anything worth while. Now this code”—he was studying the card intently—“seems to be one of a sort that our friends from Wilhelmstrasse are ridiculously fond of using. It is manifestly a book code.”

“A book code,” Jane repeated perplexedly. “I don’t understand.”

“It is very simple when two persons who wish to communicate with each other secretly both have a copy of some book they have agreed to use. They write their message out and then go through the book locating the words of the message by page, line and word. That’s what the three columns mean. Our only problem is to discover which is the book they both have. They often employ the Bible or a dictionary or—”

He stopped abruptly and studied the columns of figures.

“This code,” he went on, “on its face is from a book that has at least 544 pages. One of the pages has at least 76 lines—that’s the middle column—so the book must be set in small type.”

“What book do you suppose it is?” asked Jane interestedly. She was glad now that she had listened to Carter. She was sure she was going to like being in the service. It was all so interesting, and she was learning so many fascinating things.

“If my theory is right those letters indicate that the book used was an almanac. That’s the book that Wilhelmstrasse made use of when a wireless message was sent in cipher to the German ambassador directing him to warn Americans not to sail on the Lusitania. They betrayed themselves at the Embassy by sending out to buy a copy of this almanac. Let’s see how our theory works out.”

Taking up an almanac that lay on his desk he began turning to the pages indicated in the first column of figures, checking off the lines indicated in the second column and putting a ring around the words marked by the third column of figures.

“Let’s see—page 534—fifth line—second word—that’s (eight). Now then—page 331—that’s the chronology of the war in the almanac, so I guess we are on the right track—fifty-fourth line—sixth word—(transport).”

“Isn’t it wonderful!” cried Jane.

“Damn them,” he exploded. “I know we are on the right track. Some transports with our troops sailed this morning, and already the German spies are spreading the news, hoping to get it to one of their unspeakable U-boats.”

Quickly he ran through the rest of the cipher, writing it out as he went along:

EIGHT—TRANSPORT—SAILED—THURSDAY—15,000—INFANTRY—FIVE DESTROYERS.

As Fleck finished the message his face became almost black with rage.

“Damn them,” he cried again, “in spite of everything we do they get track of all our troop movements. Their information, whenever we succeed in intercepting it, is always accurate. If I had my way I’d lock up every German in the country until the war was over, and I’d shoot a lot of those I locked up. Until the whole country realizes that we are living in a nest of spies—that there are German spies all around us, in every city, in every factory, in every regiment, on every ship, everywhere right next door to us—this country never can win the war.”

“What does the ‘97’ at the end mean?” questioned Jane timidly, a little bit frightened at his outburst, yet more than ever realizing the vast importance of his work—and hers.

“Oh, that’s nothing. Probably old Hoff’s number. Most spies are known just by numbers.”

“Yes, of course,” said Jane, flushing as she recalled that she herself was now “K-19.” Was she a spy? Was Mr. Fleck a chief of spies? She always had looked on a spy as a despicable sort of person, yet surely the work in which they both were engaged was vital to American success at arms—a patriotic and important service for one’s country.

“I suppose,” she said thoughtfully, unwilling to pursue the chain of her own thought any further, “that there is evidence enough now to arrest old Mr. Hoff right away.”

“You bet there is,” said Mr. Fleck emphatically, “but that is the last thing I am thinking of doing yet. He is only one link in a great chain that extends from our battleships and transports there in the North River clear into the heart of Berlin. We’ve got to locate both ends of the chain before we start smashing the links. We’ve got to find who it is in this country that is supplying the money for all their nefarious work, from whom they get their orders, how they smuggle their news out. Most of all we have got to find where the end of the chain is fastened in our own navy. The traitors there are the black-hearted rascals I would most like to get. They are the ones we’ve got to get.”

“Yes, indeed,” assented Jane, suddenly recalling the navy lieutenant she had seen in the Ritz chatting so confidentially with old Otto Hoff’s nephew. Was he, she wondered, one of the links in the terrible chain? Was he the end—the American end of the chain?

“We’re certain about the old man now,” said Fleck, rising as if to indicate that the interview was at an end. “We’ve got to get the young fellow next. There is nothing in this to implicate him. That’s your job. Find out all you can about him. Get acquainted with him, if possible. That’s one of the weakest spots about all German spies. They can’t help boasting to women. Try to get to know this Fred Hoff. It’s most important.”

“I’ll do more than try,” said Jane spiritedly. “I’ll get acquainted right away. I’ll make him talk to me.”

CHAPTER V ON THE TRAIL

Few men, even fathers, realize how utterly inexperienced is the average well-brought-up girl, just emerged from her teens, in the affairs of the great mysterious world that lies about her. A boy, in his youth living over again the history of his progenitors, escapes his nurse to become an adventurer. At ten he is a pirate, at twelve a train robber, at fourteen an aviator, actually living in all his thoughts and experiences the life of his hero of the moment, learning all the while that the world about him is full of adventurers like himself, ready to dispute his claims at the slightest pretext, or to carry off his booty by prevailing physical force.

Well-brought-up girls seldom are fortunate enough to have such educative experiences. Their friends are selected for them, gentle untaught creatures like themselves. Few of them learn much of the practical side of life. A boy is delighted at knowing the toughest boy in the neighborhood. A girl’s ambitions always are to know girls “nicer” than she is. The average girl emerges into womanhood with her eyes blinded, uninformed on the affairs of life, business, politics, untrained in anything useful or practical, knowing more of romance and history than she does of present-day facts.

If Chief Fleck had understood how really inexperienced Jane Strong actually was, it is a question whether he would have ventured to entrust so important a mission to her as he had done. Jane herself, as she left his office, aroused by his revelations of the treacherous work of Germany’s spies, and uplifted by his appeal to her patriotism, felt enthusiastically capable of obeying his instructions. It seemed very simple, as he had talked about it. All she had to do was to get acquainted with the young man next door. Yet the further the subway carried her from Mr. Fleck’s office after her second visit there that morning, the more her heart sank within her, and the fuller her mind became of misgivings.

In a big city next door in an apartment house is almost the same thing as miles away. She ransacked her brain, trying to remember some acquaintance who might be likely to know the Hoffs, but failed utterly to recall any one. She reviewed all possible means of getting acquainted but could find none that seemed practical. Never in her life had she spoken to a man without having been introduced to him—except of course to Carter and Mr. Fleck, and these men, she told herself, were government officials, something like policemen, only nicer. At any rate, she knew them only in a business way, not socially. If she was to be successful in learning much about the Hoffs—about young Mr. Hoff—she felt that it was necessary to make them social acquaintances.

She must manage to meet Frederic Hoff in some proper way, but how? She thought of such flimsy tricks as dropping a handkerchief or a purse in the elevator some time when he happened to be in it, but rejected the plan as disadvantageous. “Nice” girls did not do that sort of thing, and even though she was seeking to entrap her neighbor she did not for a moment wish him to consider her as belonging to the other sort. It rather annoyed her to find that she cared what kind of an impression she made on him. What difference did it make what a German spy thought of her, especially a murderer? Yet, she argued with herself, the better the impression she made at first the more likely she would be to gain his confidence, and that she knew would delight Mr. Fleck. Was Frederic Hoff, too, really, she wondered, a spy? Her face colored as she recalled the mental picture she last had had of him, gallantly and admiringly raising his cup to her as she left the Ritz, not obtrusively or impudently, but so subtly that she was sure that no one had observed it but herself. It seemed preposterous to associate the thought of murder with a man like him.

As she entered the apartment house she was arguing still with herself about him. Her intuition told her that Frederic Hoff was a gentleman, and how could a gentleman be what Mr. Fleck seemed to think he was? As the door swung to behind her she gave a little quick breath of delight, for she had caught sight of a uniformed figure standing by the switchboard. She had recognized him at once. It was the naval lieutenant who had been at the Ritz. She heard him saying to the girl at the switchboard:

“Tell Mr. Hoff, young Mr. Hoff, that Lieutenant Kramer is here. I’ll wait for him down-stairs.”

Quick as a flash a course of action came into her mind. She saw an opportunity too good to be neglected. She hurried forward to where the lieutenant was standing, her hand outstretched, with a smile of recognition—feigned, but well-feigned—on her lips.

“Why, Lieutenant Kramer,” she cried, “how delightful. Have you really kept your promise at last and come to see the Strongs?”

She could hardly restrain her amusement as she watched the embarrassed young officer strive in vain to recall where it was that he had met her. She had relied on the fact that the men in the navy meet so many girls at social functions that it is impossible for any of them to remember all they had met.

“Really, Miss—” he stammered, struggling for some fitting explanation.

“Don’t tell me,” she warned reprovingly, “that it isn’t Jane Strong that you are here to see, after all those nice things you said to me that day we had tea aboard your ship.”

She was hoping he would not insist on going into particulars as to which ship it was. Fortunately she had been to functions on several of the war vessels, so that she might find a loop-hole if he was too insistent on details.

“Indeed, Miss Strong,” said Kramer, gallantly pretending to recall her, “I’m delighted to see you again. I’ve been intending to come to see you for ever so long, but you understand how busy we are now. In fact, it was business that brought me here to-day. I’m calling on Mr. Hoff, who lives here, to take him to lunch to discuss some important matters.”

At his last phrase Jane’s heart thrilled. What important matters could there be that a navy lieutenant could fittingly discuss with a German, with the nephew of the man whose secret code message they had just succeeded in reading? Determining within herself to keep fast hold on the beginning she had made, she masked her real thoughts and let her face express frank disappointment.

“How horrid of you,” she continued, “when I was just going to insist that you stay and have luncheon with us.”

He was protesting that it was quite out of the question when the elevator brought down her mother, whom Jane at once summoned as an ally, feeling sure that considering how many men of her daughter’s acquaintance she had met, it would be perfectly safe to keep up the deception.

“Oh, mother,” she cried, “you remember Lieutenant Kramer, don’t you? I’ve just been urging him to stay and have luncheon with us. Do help me persuade him.”

“Of course I remember Mr. Kramer,” fibbed the matron cordially, all unaware of her daughter’s duplicity. “Do stay, Mr. Kramer, and have luncheon with Jane. I ordered luncheon for four, expecting to be home, and now I’ve been called away, but your aunt is there to chaperone you. It spoils the servants so to prepare meals and have no one to eat them, to say nothing of displeasing Mr. Hoover. It’s really your duty—your duty as a patriot—to stay and prevent a food-waste.”

“I’ve just been trying to explain to your daughter that I was taking Mr. Hoff to luncheon with me. Here he is now.”

Mrs. Strong’s eyes swept the tall figure approaching appraisingly and apparently was pleased with his aspect. As Mr. Hoff was presented she hastened to include him in the invitation to luncheon.

“Have pity on a poor girl doomed to eat a lonely luncheon by her parent’s neglect,” urged Jane. “Really, you must come, both of you. Nice men to talk to are so scarce in these war times that I have no intention of letting you escape.”

“I’m in Kramer’s hands,” said Frederic Hoff gallantly, “but if he takes me to some wretched hotel instead of accepting such a charming invitation as this, my opinion of him as a host will be shattered.”

“But,” struggled Kramer, realizing that it must be a case of mistaken identity and sure now that he never had met either Jane or her mother before, “we have some business to talk over.”

“Business always can wait a fair lady’s pleasure,” said Hoff. “Is this ruthless war making you navy men ungallant?”

With a mock gesture of surrender, and as a matter of fact, not at all averse to pursuing the adventure further, Lieutenant Kramer permitted Jane to lead the way to the Strong apartment.

Soon, with the familiarity of youth and high spirits, the three of them were merrily chatting on the weather, the war, the theater and all manner of things. Jane, in the midst of the conversation, could not help noting that Hoff had seated himself in a chair by the window where he seemed to be keeping a vigilant eye on the ships that could be seen from there. Even at the luncheon table he got up once and walked to the window to look out, making some clumsy excuse about the beautiful view.

Determined to press the opportunity, Jane endeavored to turn the conversation into personal channels.

“You are an American,” she said turning to Hoff, “are you not? I’m surprised that you are not in uniform, too.”

“A man does not necessarily need to be in uniform to be serving his government,” he replied. “Perhaps I am doing something more important.”

“But you are an American, aren’t you?” she persisted almost impudently, driven on by her eagerness to learn all she possibly could about him.

“I was born in Cincinnati,” he replied hesitantly.

She could not help observing how diplomatically he had parried both her questions. Mentally she recorded his exact words with the idea in her mind of repeating what he had said verbatim to her chief.

“Then you are doing work for the government?”

Intensely she waited for his answer. Surely he could find no way of evading such a direct inquiry as this.

“Every man who believes in his own country,” he answered, modestly enough, yet with a curious reservation that puzzled her, “in times like these is doing his bit.”

She felt far from satisfied. If he was born in America, if he really was an American at heart, his replies would have been reassuring, but his name was Hoff. His uncle was a German-American, a proved spy or at least a messenger for spies. If her guest still considered Prussia his fatherland the answers he had made would fit equally well.

“You’re just as provokingly secretive as these navy men,” she taunted him. “When I try to find out now where any of my friends in the navy are stationed they won’t tell me a thing, will they, Mr. Kramer?”

“I’ll tell you where they all are,” said Lieutenant Kramer. “Every letter I’ve had from abroad recently from chaps in the service has had the same address—‘A deleted port.’”

“I really think the government is far too strict about it,” she continued. “My only brother is over there now fighting. All we know is that he is ‘Somewhere in France.’ War makes it hard on all of us.”

“Yet after all,” said Hoff soberly, “what are our hardships here compared to what people are suffering over there, in France, in Belgium, in Germany, even in the neutral countries. They know over there, they have known for three years, greater horrors than we can imagine.”

The longer she chatted with him, the more puzzled Jane became. He seemed to speak with sincerity and feeling. Her intuition told her that he was a man of honor and high ideals, and yet in everything he said there was always reserve, hesitation, caution, as if he weighed every word before uttering it. Intently she listened, hoping to catch some intonation, some awkward arrangement of words that might betray his tongue for German, but the English he spoke was perfect—not the English of the United States nor yet of England, but rather the manner of speech that one hears from the world-traveler. Question after question she put, hoping to trap him into some admission, but skilfully he eluded her efforts. She decided at last to try more direct tactics.

“Your name has a German sound. It is German, isn’t it?” she asked.

“I told you I was born in Cincinnati,” he answered laughingly. “Some people insist that that is a German province.”

“But you have been in Germany, haven’t you?”

“Why do you ask?”

“I was wondering if you had not lived in that country?”

“I could not well have been there without having lived there, could I?”

Kramer came to her rescue.

“Of course he has lived there. Mr. Hoff and I both attended German universities. That was what brought us together at the start—our common bond.”

“Did you attend the same university?” asked Jane. She felt that at last she was on the point of finding out something worth while.

“No,” said Kramer, “unfortunately it was not the same university.”

She caught her breath and blushed guiltily. If Mr. Kramer had attended a German university he could not be an Annapolis graduate. He must be a recent comer in the American navy. She knew that since the war began some civilians had been admitted. It had just dawned on her that if this was the case, since visiting on board ships was no longer permitted, it clearly was impossible for her to have met him at any function on a warship. He must have known all along that she knew she never had met him. He must have been aware, too, that her mother did not know him. She felt that she was getting into perilous waters and fearful of making more blunders refrained from further questions. A vague alarm began to agitate her. If he had detected her ruse when she first had spoken to him, why had he not admitted it? What had been his purpose in accepting her invitation and in bringing into it his German friend, Mr. Hoff?

The ringing of the telephone bell came as a welcome interruption. A maid summoned her to answer a call, and excusing herself from the table she went to the ’phone desk in the foyer.

“Hello, is this you, Miss Strong?”

It was Carter’s voice, but from the anxious stress in it she judged that he was in a state of great perturbation.

“Yes, it is Jane Strong speaking,” she answered.

“You know who this is?”

“Of course. I recognize your voice. It’s Mr. C—”

A warning “sst” over the ’phone checked her before she pronounced the name and starting guiltily she turned to look over her shoulder, feeling relieved to see the two men still chatting at the table, apparently paying no attention to her.

“I understand,” she answered quickly. “What is it?”

“You know that book I told you I was going to buy?”

“Yes, yes!”

“It’s not there.”

“What’s that? The book is gone!”

“The book is there all right, but it’s not the book I want.”

“Are you sure,” she questioned, “that you looked at the right book?”

“I looked at the one you told me to.”

“Are you certain—the fifth book on the second shelf.”

Had he been standing there listening? How much had he heard?

She heard a movement behind her and turning quickly saw Frederic Hoff standing behind her, his hat and stick in hand. Panic-stricken, she hung up the receiver abruptly. Had he been standing there listening? How much had he heard? He would know, of course, what “the fifth book on the second shelf” signified. Had her carelessness betrayed to him the fact that he and his uncle were being closely watched? Anxiously she studied his face for some intimation of his thoughts. He was standing there smiling at her, and to her agitated brain it seemed that in his smile there was something sardonic, defying, challenging.

“I cannot tell you, Miss Strong, how much I have enjoyed your hospitality. You made the time so interesting that I had no idea it was so late. You will excuse me if I tear myself away at once. I have some important business that demands my immediate attention.”

“I hope you’ll come again,” she managed to stammer, “and you, too, Mr. Kramer.”

White-faced and terrified she escorted them out, leaving the telephone bell jangling angrily. As the door closed behind them, she sank weak and faint into a chair, not daring yet to go again to the ’phone until she was sure they were out of hearing.

What was the “immediate business” that was calling them away so suddenly? She was more than afraid that her incautious use of the phrase “the fifth book on the second shelf” had betrayed her. What else could it mean? Why else would they have departed so abruptly?

Mustering up her strength and courage she went once more to the ’phone.

“Hello, hello, is that you, Miss Strong? Some one cut us off,” Carter’s voice was impatiently saying.

“Hello, Mr. Carter,” she called, “this is Jane Strong speaking. Where can I see you at once? It’s most important.”

“I’ll be sitting on a bench along the Drive two blocks north of your house inside of ten minutes.”

“I’ll meet you there,” she answered quickly, with a feeling of relief.

The situation was becoming far too complicated, she felt, for her to handle alone. Carter would know what to do. If Hoff and Kramer had learned from her about the trailing of old Hoff, the sooner it was reported to more experienced operatives than she was the better.

“Don’t speak to me when you see me sitting on the bench,” warned Carter. “Just sit down there beside me and wait till I make sure no one is watching us. I’ll speak to you when it’s safe.”

“I understand,” she answered. “Good-by.”

As she hastened to don her hat and coat she was almost overwhelmed by a revulsion of feeling. Two days ago the world about her had seemed a carefree, pleasant, even if sometimes boresome place. Now she shudderingly saw it stripped of its mask and revealed for the first time in all its hideousness, a place of murders and spying and secret machinations. People about her were no longer more or less interesting puppets in a play-world. They were vivid actualities, scheming and planning to thwart and overcome each other. Almost she wished that her dream had been undisturbed and that she had not been waked up to the realities. Almost she was tempted to abandon her new-found occupation.

Then, once more, a feeling of patriotic fervor swept over her. She thought of her brother fighting somewhere in the trenches. She pictured to herself the other brave soldiers in the great ships in the Hudson. She remembered the evil plotters with their death-dealing bombs, striving to bring about a ghastly end for them all before they might strengthen the lines of the Allies. She thought, too, of those humanity-defying U-boats, forever at their devilish work, guided to their prey by crafty, spying creatures right here in New York, more than likely by the very people next door.

With her pretty lips set in a resolute line she left the house and walked rapidly north. Come what may she would go on with it. Her country needed her, and that was all-sufficient.

CHAPTER VI THE MISSING MESSAGE

After Jane left Carter at the drug-store, he did not cross immediately to the bookshop opposite. His detective work was not of that sort. He strolled leisurely around the corner long enough to give some directions to his two aides waiting there and then, moving across the street, paused in front of the window of books as if something there had attracted his attention. All the while he was keeping a sharp eye for any person who looked as if they might be connected in any way with old Hoff. Satisfied that his entrance was unobserved he strolled casually in and began looking over the volumes in the lending library. The lone clerk in the store—a young woman—at first volunteered some suggestions, but as they went unheeded she returned to her work of posting up the accounts.

As soon as her attention was occupied Carter moved at once to the end of the shelf that Miss Strong had indicated and removed the fifth book. To his amazement he found nothing whatever concealed between the leaves. The books on either side on the same shelf failed to yield up anything. He tried the shelf above and the shelf below. Perhaps Miss Strong had been mistaken in the directions. He examined the books at the other end. There was nothing there. He recalled that the girl had said that no one except two girls had entered the store between the time she had discovered and copied the cipher and the time of his arrival. If these girls had not taken the message away there could be only one other explanation—the clerk in the bookstore must have removed it and concealed it somewhere.

“Which of the war books do you think the best?” he asked for the purpose of starting a conversation.

“There’s that many it is hard to say, sir,” the young woman answered.

Something in her inflection made him look sharply at her. Her accent surely was English, or possibly Canadian. A few judicious questions quickly brought out the information that she came from Liverpool and that she had three brothers in the British army. Carter decided that it was preposterous to suspect her of being in league with German agents. There was only one other thing that could have happened. Some one else—some one who had eluded Miss Strong’s notice—had removed the cipher message.

Promptly he had telephoned to her to meet him. He was glad that he had done so, for her evident perturbation as she answered the ’phone both interested and puzzled him. Pausing just long enough to report to Chief Fleck, he hastened to the rendezvous, arriving there first. He selected a bench apart from the others, where the wall jutted out from the walk, and seating himself, idled there as if merely watching the river. In obedience with his instructions Jane, when she arrived, planted herself nonchalantly on the same bench, and paying no attention to him, pretended to be reading a letter.

Presently Carter rose and stretching himself lazily, as if about to leave, turned to face the Drive, his keen eyes taking in all the passers-by. Apparently satisfied, he sat down abruptly and turned to speak to the girl beside him.

“All right, K-19,” he said, “it’s safe. Now we can talk.”

“I’ve got such a lot to tell,” cried Jane.

“First,” said Carter, “just where did you put that cipher message when you put it back?”

“What!” cried the girl, her face blanching, “wasn’t it there? Didn’t you find it?”

Carter shook his head.

“It must be there,” she insisted. “Are you sure you looked in the right book—the fifth book from the end on the second shelf on the up-town side of the store.”

“It’s not there. I examined every book there, on the shelves above and below and at the other end, too.”

“The clerk in the store, that girl—must have hidden it,” cried Jane with conviction.

“That’s not likely. She’s an English girl—from Liverpool. She has three brothers fighting on the Allies’ side. We can leave her out of it.”

“Who else could have taken it?”

“There’s only one answer,” said Carter slowly and impressively. “Some one went into that store between the time you copied the message and the time I met you at the drug-store. You told me no one but a couple of girls had entered. Was there any one else? Think—think!”

“There was no one,” said Jane thoughtfully, “no one except the two girls together. I never thought of suspecting them.”

“What did they look like? Could you identify them?”

“I did not notice them particularly,” Jane confessed. “I was expecting Mr. Hoff’s confederate to be a man.”

“They’re using a lot of women spies,” asserted Carter. “Don’t you remember what the girls looked like?”

“One of them,” said Jane thoughtfully, “wore an odd-shaped hat, a sort of a tam with a red feather.”

“Would you know the hat again if you saw it?”

“I think—I’m sure I would.”

“Well, that’s something. Watch for that hat, and if you ever see it again trail the girl till you find out where she lives. If you locate her telephone Mr. Fleck at once. And now, what has happened to you?”

“I’ve so much to tell, important, very important, I think.”

She hesitated, wondering how much Carter was in the chief’s confidence. Did he know the import of the cipher message she had discovered? Ought she to talk freely to him?

“Do you know what those numbers meant?” she asked.

“Yes,” he replied, “about the eight transports sailing. The Chief told me about it.”

“Well,” she said, with a sigh of relief, “I have become acquainted with young Mr. Hoff already. I’ve just had luncheon with him.”

“That’s fine,” he cried enthusiastically. “A lucky day it was I ran across you.”

“When you ’phoned me he was there in our apartment, he and a navy lieutenant, Mr. Kramer.”

Attentively he listened as she told of the ruse by which she had inveigled them into coming to luncheon, reminding him that it was the same naval officer that he himself had seen in close conversation with Hoff at the Ritz the day before. He nodded his head in a satisfied way.

“They are together too much to be up to any good,” he commented. “Tell me the rest. What made you so rattled when I ’phoned you?”

He listened intently as she told of finding young Hoff standing right behind her as she had inadvertently mentioned aloud “the fifth book.”

“Do you suppose,” she questioned anxiously, “that he overheard me and understood what we were talking about? He left right away after that. I do hope I didn’t betray the fact that they are being watched.”

“We can’t tell yet,” said Carter. “The precautions they take and the roundabout methods they have of communicating with each other show that all Germany’s spies constantly act as if they knew they were under surveillance. In fact, I suppose every German in this country, whether he is a spy or not, can’t help but notice that his neighbors are watching him—and well they might.”

“I don’t see why,” cried Jane, “Mr. Fleck did not have old Mr. Hoff locked up right away. He could not do any more damage then, or be sending any more messages about our transports.”

“That wouldn’t have done the least bit of good,” said Carter decisively. “Watching our transports sail and spreading the news is only one of many of their activities. Somewhere in this country there is a master-council of German plotters, directing the secret movements of many hundreds, perhaps many thousands of spies and secret agents. They have their work well mapped out. They have men fomenting strikes in the government shipyards and stirring up all kinds of labor troubles. Others are busy making bombs and contriving diabolical methods of crippling the machinery in munition plants. A flourishing trade in false passports is being carried on, enabling their spies to travel back and forth across the Atlantic in the guise of American business men, ambulance drivers, Red Cross workers and what not. Still others of their agents are detailed to arrange for the shipping of the supplies Germany needs to neutral countries. By watching shipping closely they gather information, too, that is of value to the U-boat commanders. Every time there is any sort of activity against the draft, or peace meetings, or Irish agitation, we find traces of German handiwork. We have dismantled and sealed up every wireless plant we could find in America except those under direct government control, yet we are positive that every day wireless messages go from this country somewhere—perhaps to Mexico or South America, and from there are relayed to Germany, probably by way of Spain. Think of the enormous amount of money required to finance these operations and keep all these spies under pay. While we try to thwart their plans as we find them, all our efforts are constantly directed toward discovering who controls and finances their damnable system. We seldom if ever arrest any of the spies we track down, but keep watching, watching, watching, hoping that sooner or later the master-spy will be betrayed into our hands.”

“You don’t think then,” said Jane disappointedly, “that old Mr. Hoff is one of the important spies.”

“We can’t tell yet. He may be just one of the cogs—perhaps what they call a control-agent. We don’t know yet. Germany has been building up her spy system forty years, and it is ingenious beyond imagination. Her codes are the most difficult in the world. It took the French three years and a half to decipher a code despatch from Von Bethmann Hollweg to Baron von Schoen. By the time they had it deciphered in Paris the Germans had discovered what they were doing and had changed the code. It is seldom any one of the German spies knows much about the work that other spies are doing. The rank and file merely get orders to go and do such a thing, or find out about such a thing. Often they are not told what they are doing it for. They obey their orders implicitly in detail and make their reports, get new orders and go on to do something else. Only their master spy-council here knows what the summary of their efforts amounts to. Arresting old Hoff, or a dozen more like him, would not cripple them much. Other men would be assigned in their places, and the nefarious work would go on.”

“I don’t know,” insisted Jane thoughtfully. “I believe that old Mr. Hoff is a far bigger spoke in the wheel than you think. I watched his face as I followed him this morning. He is a man of great intelligence, and I should judge a man of education.”

“They’d hardly be using a man of that sort to carry messages,” objected Carter. “Maybe you’re right. We have not watched him long enough to find out. We’ve got nothing yet on the young fellow. Maybe he’s the real boss of the outfit. At any rate he is the one the Chief is anxious to have you keep tabs on. Are you to see him again?”

“Oh, yes,” the girl answered quickly, a touch of color coming to her face, “I think so. I asked him to come to see me. I think—in fact I’m sure—he will. Do you want me to watch the bookshop to see if they leave any more messages there?”

“No,” said Carter. “I’ve got one of my men assigned to that. You keep after the young fellow. Say, does your father keep an automobile?”

“Yes, but it’s been put up for the winter. We’re going to bring it out as soon as Dad can find a chauffeur. Our man—the one we had last year—has been drafted, and good chauffeurs are scarce now. Why did you ask?”

“I’ll find you a chauffeur,” said Carter decisively.

“You mean”—Jane hesitated—“a detective?”

Carter grinned.

“An agent like you and me. K-27 is an expert chauffeur and mechanic with fine references. His last job was with the British High Commission, and they gave him good testimonials.”

“What do you want him to do?”

“Driving the Strong car makes a good excuse for him to be around without exciting suspicion. He might even come up-stairs once in a while to get orders or do little repair jobs around the apartment. Some day, supposing the people next door were all out, he might even succeed in planting a dictograph so that you could sit there in your room and hear all that was going on and what the Hoffs talked about. That would help a lot. If ever he was caught prowling about the hall, the fact that he was your chauffeur would provide him with an alibi. Do you think you can fix it up with your father?”

“I’m sure of it. When can he come?”

“The sooner the better—to-night—to-morrow.”

“I’ll tell Dad at dinner to-night that I’ve learned of a good chauffeur and have asked him to come in at eight this evening.”

“Fine,” said Carter. “He’ll be there. And don’t forget to report once a day to the Chief.”

“I won’t.”

“And if anything unexpected turns up,” said Carter, “and you need help, take a good look at that nurse that is passing.”

Jane turned curiously to inspect a buxom girl in a drab nurse’s costume who was wheeling a baby carriage along the sidewalk near-by. Seeing herself observed the girl stopped, and at a sign from Carter wheeled her charge up to where they were standing.

“K-22,” said Carter, “I want to introduce you to K-19.”

Gravely the two girls, nodding, inspected each other.

“She always wears a blue bow at her neck,” Carter added, “so you can recognize her by that.”

The girl smilingly nodded again and wheeled the carriage on up the Drive.

“Who is she?” Jane asked eagerly, turning to Carter.

“Just K-22,” said the agent, “and all she knows about you is that you are K-19. That’s the way we work in the service mostly. The less one operative knows about another the better, for what you don’t know you can’t talk about.”

“Doesn’t she even know my name?” persisted Jane.

“She may have found it out for herself while she has been watching the Hoffs, but we didn’t tell her. Nobody in the service knows who you are except the Chief and myself—and of course K-27 will have to know if he takes the chauffeur’s job.”

“What is his name?”

“I don’t know yet,” said Carter gravely. “I haven’t seen his references, so I don’t know what name they are made out in. You can find out what to call him when he reports to-night. You’ll see that he gets the job?”

“Indeed I will,” answered Jane, experiencing a sense of relief at the prospect of having some one at hand in the household with whom she could discuss her activities.

And as she had anticipated she had little difficulty in interesting her father in the subject of a new chauffeur. Mr. Strong for several days had been trying to find one without success.

“You say this man’s last place was with the British High Commission.”

“Some one of the girls was telling me,” she prevaricated. “I asked her to tell him to come here to-night at eight. He ought to be here any minute.”

Presently the candidate for the place was announced.

“Mr. Thomas Dean to see about a chauffeur’s position,” the maid said as she brought him in, and while her father questioned him, Jane studied him carefully.

He could not be more than thirty, she decided, and the voice in which he answered her father’s questions was surely a cultivated one. It would not have surprised her in the least to have learned that he was a college man. Even in his neat chauffeur’s uniform he seemed every inch a gentleman. He had been driving a car for twelve years, he explained. No, he did not drink and had never been arrested for speeding.

“Are you a married man?”

Jane listened curiously for his answer to this question of her father’s. Surely it would be far more interesting if he wasn’t. Of course, he was a chauffeur and a detective, but somehow she could not help feeling, perhaps because of his easy manner, that more than likely most of the cars he had driven were cars that he himself had owned. K-27 she decided was going to be quite a satisfactory partner to work with.

“There’s just one thing,” said her father. “You say you are not married. I can’t understand why it is that you are not in the army.”

“I am not eligible,” said Thomas Dean calmly, though Jane thought she could detect a twinkle in his eye. “One of my legs has been broken in three places.”

“But there are things a young fellow can do for his country besides marching,” insisted Mr. Strong. “The government needs mechanics, too.”

“I know,” said Thomas Dean, almost humbly, “but I have a mother, and my father is dead.”

Jane smiled a little to herself at his answer. She noted how carefully he had avoided saying anything about having a mother to support. It would not have surprised her in the least to have learned that he was a millionaire, yet her father, ordinarily shrewd in judging men, apparently was satisfied.

“Supporting a mother, I suppose, comes first,” he said. “Well, Dean, when can you come?”

“To-morrow morning if you like,” the new chauffeur answered, nodding gravely to Jane as he withdrew.

Mr. Strong, as soon as they were alone, spoke enthusiastically about the young man, complimenting Jane on having discovered him, and as he did so a revulsion of feeling swept over her. For the first time she realized into what duplicity her work for the government was leading her. She had pledged her word to Chief Fleck that she would keep her activities an absolute secret even from her parents. Already she was deceiving them, bringing into the household an employee who really was a detective, a spy. She was tempted to tell her father, at least, what she was doing. He, she knew, was filled with a high spirit of patriotism. While he might not wholly approve of what she herself was doing she might be able to convince him of the necessity of it. If she could only tell him, her conscience would not trouble her, but there was her promise—her sacred promise; she couldn’t break that.

While with troubled mind she debated with herself between her duty to her parents and her duty to her country, one of the maids came in with a box of flowers for her.

Eagerly she cut the string and opened the box. Chief Fleck especially wanted her to cultivate young Hoff’s acquaintance. If her suspicion as to the sender were correct, she could feel that she had made an auspicious beginning.

In a tremor of excitement she snatched off the lid of the box and tore out the accompanying card from its envelope.

“Mr. Frederic Johann Hoff,” it read, “in appreciation of a most profitable afternoon.”

Wondering at the peculiar sentiment of the card she tore off the enclosing tissue paper from the flowers. Orchids, wonderful, delicately tinted orchids, nestled in a sheaf of feathery green fern—five of them.

“Five orchids—the fifth book—a profitable afternoon.”

Jane felt sure now she had betrayed the government’s watchers to at least one of the watched.

CHAPTER VII THE WOMAN ON THE ROOF

It is amazing how much information on any given subject any one—even a wholly inexperienced person like Jane Strong—can acquire within a few days when one’s mind is set resolutely to the task. It is much more amazing how much one can learn when aided and abetted by an experienced chauffeur, or more properly speaking a mysterious and cultured secret service operative, masquerading as an automobile driver.

Who Thomas Dean was, why he was in the secret service, and what his real name was, were questions that kept perpetually puzzling Jane. In the presence of her father and mother, so skilful an actor was he that it was hard to believe him anything but what he appeared to be, a respectful, intelligent and prompt young man who knew the traffic regulations and the anatomy of automobiles. When he and Jane were by themselves he invariably threw off his mask to some extent. He became the director instead of the directed, though never letting anything of the personal relation creep in. That he was college-bred, Jane felt certain. He spoke both German and French much better than she did. He occasionally used words that no ordinary chauffeur would be likely to know the meaning of. Sharing the secret of such a mission as theirs, they quickly found themselves on a friendly basis, yet the girl hesitated whenever her curiosity prompted her to try to find out anything that would reveal his identity. There was always present the feeling that any exhibition of undue curiosity on her part would be a disappointment to her employer. The chief disapproved of curiosity except on one subject—what the Germans were doing.

Many things Jane and her aide learned about the Hoffs in the days following Thomas Dean’s coming, reporting them all as directed. Of how much or of how little value her discoveries were Jane had no means of knowing. Chief Fleck seemed satisfied but was always urging her to acquire more information and more details, always details. Dean, too, had seconded the warning about observing even what seemed to be insignificant trifles.

“Most of the Germans,” he said to her, “you will find are very methodical. They like to do things according to schedule. For instance, I learned yesterday that old Hoff and his nephew frequently go off on all-day automobile trips. They always go on Wednesday.”

“Are they going to-morrow?”

“The presumption is that they will. They have done so every Wednesday for six weeks.”

“Can’t we follow them in our car?” cried the girl, “and see what they are up to?”

Dean shook his head.

“The Chief is looking out for that. There is more important work for us to do right here. I want to try to install a dictograph in their apartment.”

“How exciting.”

“You must find some excuse for me to come up into your apartment and see to it that none of your people are about.”

“That will be easy. Mother and Aunt will be out all day, and it is cook’s afternoon off. I can easily send the maids out.”

“But that’s not all. There is the Hoffs’ servant to be disposed of.”

“I don’t see how I can manage that,” said Jane. She could think of no possible way of overcoming that difficulty.

“She’s an old German woman—Lena Kraus,” continued Dean. “I’ve found out that she always washes on Wednesdays. When she goes up on the roof in the afternoon to get the clothes will be our time. It will be your job to see that she stays there until I am through. It will not take me more than half an hour.”

“But what will I do if she starts to come down? How will I stop her?”

“You’ll have to use your wits. Keep her talking as long as you can. When she starts down come with her. Press the elevator button four times. I’ll leave the door of the Hoff apartment open and very likely will hear it in time to get away.”

“But how’ll you get their door open?”

Dean smilingly drew forth a key.

“I borrowed the superintendent’s bunch last night, pretending I had lost the key to my locker in the basement. I knew he had a master-key that unlocks all the apartment doors, and there was no trouble in picking it out. I had some wax in my hand and made an impression of it right under his nose.”

“How clever,” cried Jane, “but suppose the Hoffs do not go off to-morrow. What will we do then?”

“You are taking tea with young Hoff this afternoon, aren’t you?”

“Yes,” said Jane, “that is, he asked me to. I am to meet him at the Biltmore at five.”

“When you’re with him propose doing something together to-morrow afternoon. See what he says.”

“That’s an excellent idea. I’ll ask him to go to the matinée with me.”

“That will do splendidly. Has he been with that navy officer lately?”

“Not since Sunday, to my knowledge. I wonder if old Mr. Hoff has left any more cipher messages at the bookshop?”

“No,” said Dean, “he hasn’t. The place has been constantly watched, but he hasn’t been near it since that first day.”

“I’m afraid,” sighed Jane despondently, “I betrayed the fact that we were watching them to the nephew. He overheard me talking to Carter about the ‘fifth book,’ and of course he knew what it meant. I’m certain the old man is still reporting about our transports. Every day I can hear some one telephoning to him. He waits for the message, and then he goes out.”

“He certainly is expert in eluding shadowers,” admitted Dean. “Every day he has been followed, but always he manages to give the operatives the slip. He must know he is being watched.”

“I’m anxious to know what the nephew will say to me to-day,” said Jane. “I know he knows what I am doing. He looks at me in such an amusedly superior way every time he sees me.”

“Be careful about trying to pump him,” cautioned Dean. “He strikes me as by far the more intelligent of the two. It would not surprise me in the least if he were not old Hoff’s nephew at all, but really his superior, sent over especially by Wilhelmstrasse to take charge of the plotters. He doesn’t in the least resemble old Hoff.”

“No indeed, he doesn’t,” admitted Jane. “He certainly is clever, too. We haven’t learned a single thing that incriminates him, have we?”

“Nothing definite, yet everything taken together looks damaging enough. Here is a young German of military age and appearance, who arrived from Sweden just before we went into the war. He has plenty of money and spends his time idling about New York, in frequent communication with at least one navy officer. He selects a home overlooking the river from which our soldiers are departing for France. You yourself saw him pursuing K-19—the other K-19—who a few hours afterward was found murdered.”

“Things don’t look right,” Jane agreed, yet a few hours later as she sat opposite the young man at tea, she found herself doubting. It seemed incredible, impossible, that Frederic Hoff could be a murderer. Her instinctive sense of justice forced her to admit that it was hard for her to believe him even a spy. He seemed so cultured, so clean, so straightforward, so nice. If she had not seen that unforgettable look of hate on his face that night as she watched him from the window she could not, she would not have believed evil of him.

The tremor of nervous excitement in which she met him quickly passed, and she found herself once more chatting intimately with him and enjoying it. He talked well on practically all subjects, showing reserve only when she tried to draw him out about himself. Her previous experiences with the opposite sex had taught her that most men’s favorite topic of conversation is themselves, but Mr. Hoff appeared to be the exception. Adroitly he baffled all her efforts to get him to discuss his family, his achievements, or his past, even when she sought to encourage intimacy by telling about her brother who was abroad in Pershing’s army.

“You must let me be your big brother while he is away,” her escort had suggested gallantly.

“All right, brother,” she had challenged him. “I’ll take you on at once. I have seats for a matinée to-morrow. I’d much rather go with a brother than with one of the girls.”

“I would be delighted,” he answered unsuspectingly, “but unfortunately I have an engagement that takes me out of town.”

“We’ll go next week, then—Wednesday.”

“A week is too long to wait. Let me take you to a matinée on Saturday.”

Jane hesitated. At times her conscience troubled her not a little. While satisfied that the importance of her trust wholly justified her actions, she disliked any deception of her family.

“Wouldn’t it be better,” she parried, “if you came to call on me some evening first? You’ve only just met my mother, and I would like you to know Dad, too.”

“May I?” he cried with manifest pleasure. “How about to-morrow evening?”

“That’s Wednesday,” she answered slowly. That was the day she and Dean were planning to put in a dictograph. She wondered at herself calmly carrying on this casual conversation with the man she was planning to betray. Coloring a little from the very shame of it, she continued, “How about making it Thursday evening?”

“Delighted,” cried Hoff, “and about Saturday’s matinée—what haven’t you seen?”

Glad for the respite of at least twenty-four hours, Jane, as they talked, watched his face, his expression, his eyes. Regardless of the things she believed about him, he impressed her as honest and sincere. Certainly there was no mistaking the fact that his liking for her and his delight in her society were wholly genuine. Her heart warned her that it was his intention to press their new-formed acquaintance into close intimacy. Was he, she wondered, like herself, pretending friendship merely to unmask secrets for his government? No, she could not, she would not believe it. She felt sure that his admiration was unfeigned. Something told her that quickly his ardor and determination might lead her into embarrassing circumstances. He might even ask her to marry him. For a moment she was overcome with timidity and tempted to stop short on her new career, but there came to her the thought of the brave Americans in the trenches, of the soldiers at sea, of the brutal, lurking U-boats, and sternly she put aside all personal considerations.

“You spoke of going out of town,” she said when the subject of the matinée had been disposed of. “Don’t you find train travel rather disagreeable these days?”

“Fortunately I’m motoring.”

“That will be nice, if you don’t have to travel too far.”

“It is quite a distance for one day, but I am used to it. I make the trip often.”

Feeling that at least she had learned something, Jane rose to go. She knew that both the Hoffs would be out of the way to-morrow. The inference from his last remark was that they were going to the same place they had gone on previous Wednesdays. That was something to report to Mr. Fleck.

“My car is outside,” she said as they rose. “Can’t I take you home?”

“Sorry,” said her host, “but I am dining here to-night. Lieutenant Kramer is to join me.”

“Remember me to him,” she said as he escorted her to the automobile, driven by Dean.

A block away from the hotel she tapped on the glass, and as Dean brought the car to a stop she climbed into the seat beside him. Only a week ago she would have criticized any girl who rode beside the chauffeur. In fact she had spoken disapprovingly of a girl in her own set who made a habit of doing it, but now she never gave it a thought. Many things in her life seemed to have assumed new aspects and values since she had entered on a career of useful activity. In her was rapidly developing something of her father’s ability and directness. As she wanted to talk confidentially with Dean, she went the easiest way about it, entirely regardless of appearances.

“Apparently you carried it off well,” he commented.

“I hope so,” she answered, coloring a little. “They’re making their usual Wednesday motor trip.”

“He did not tell you their destination?”

“No, but Lieutenant Kramer is dining with him to-night at the Biltmore.”

“Fine. Those things the Chief can take care of. That leaves the way clear for us to-morrow afternoon.”

“What excuse will I make for having you come up to the apartment?”

“You want me to change some pictures. That will account for the wire if I’m caught.”

“I hope no one sees you.”

“Nobody’ll see me but the elevator man, and he’ll think nothing of it.”

Apparently, too, Dean was right, for the next afternoon he entered the Strong apartment carrying a suitcase in which was concealed his apparatus and the necessary wire.

“Hurry,” cried Jane, who was waiting for him. “The Hoffs’ maid has just gone up on the roof.”

“We can safely give her at least a few minutes,” said Dean setting to work to make a hole through the wall into the apartment adjoining. Just as he had finished making it and had pushed one end of the wire through, the telephone bell rang, and Jane in dismay sprang to answer it.

“Disguise your voice,” warned Dean. “If it is a caller say there is no one home.”

“It was Lieutenant Kramer calling,” said Jane as she returned.

“Did he recognize your voice?”

“I don’t think so.”

“What did he say?”

“He said to tell Miss Strong that he had called.”

“Then he didn’t suspect you.”

“Isn’t there danger, though, that he may come up to the Hoff apartment?”

Dean sprang to the window and looked out at the street below.

“No, there he goes up the street. He evidently did not try to see if the Hoffs were at home. That’s funny.”

“Why funny?”

“It means of course that he, too, knows about those Wednesday trips the Hoffs make.”

Cautiously he opened the door into the public hall. There was no one about. Catlike in swiftness and silence he moved to the Hoff door and inserted his new-made key. It worked perfectly.

“Now,” he whispered to Jane, “to the roof—quick. I must not be taken by surprise. Give me at least ten minutes more—fifteen if you can.”

Quickly he passed inside, closing the door behind him all but a barely noticeable crack, as Jane rang for the elevator and bade the operator take her to the roof. As she emerged there and stood waiting for the elevator to descend again, an ornamental lattice screened her from the rest of the roof. Cautiously and curiously she peered between the slats, trying to see what the Hoff servant was doing at the moment. She decided that she would not reveal her presence until the woman made ready to go down-stairs.

As from behind her screen she scanned the roof she espied old Lena over on the side next the river bending over a half-filled basket of clothes, apparently putting into the basket some of the freshly dried laundry from the lines extending all over the roof. As Jane watched her the old woman straightened herself up and cast a cautious glance about. Apparently satisfied that she was alone she whipped out something from a pocket in her apron and turned in the direction of the river.

Jane gasped in amazement, a thrill of excitement sweeping over her at this new discovery. It was plain that the old servant was studying the transports in the river below through a pair of powerful field glasses. Curiously Jane observed her, wondering what she was trying to ascertain, wondering if through the glasses she was able to identify the battleships and other boats. Old Lena’s next move was still more puzzling. Hastily dropping her glasses into the basket she began to hang again on the line some of the clothes. They were handkerchiefs, Jane noted interestedly, one large red one, and the rest white, some large, some small, a whole long row of nothing but handkerchiefs.

All at once it came to Jane what it must mean. The arrangement of the handkerchiefs must be some sort of a code. She studied the way they were placed, committing the order to memory. “Red—two large—one small—one large—one small.” Of course it was a code, a signal to some one aboard one of the ships.

The line of handkerchiefs completed old Lena once more took up her glasses, first looking around as before to see if any one were on the roof. How Jane wished that she, too, could see the ships from where she stood. Was some traitor in the navy wigwagging to the old woman? She was tempted to spring forward and seize her and stop this dastardly signalling, but she remembered her duty. She was there to see that Dean was not surprised by old Lena’s return. So long as the woman kept signalling he was safe.

Once more the laundress dropped her glasses and began frantically rearranging the handkerchiefs. Again Jane noted their order—red—two small—one large—three small—two large. Again the laundress resorted to the glasses, and at last, apparently satisfied, began taking down the rest of the laundry and making ready to leave the roof. Trying to act as if she had just arrived, Jane stepped boldly forward.

“I wonder,” she said approaching the woman, “if you can tell me where I can find a good laundress.”

“Nicht versteh” said old Lena, eyeing her suspiciously and hostilely, and at the same time attempting to pass her with the basket of clothes.

Deliberately blocking the way, Jane repeated her question, this time in German, feeling thankful that her language studies at school were not wholly forgotten and that they had included such practical phrases as those required to hire and discharge maids and complain about the quality of their work.

“I know no one,” the old woman answered her, this time in English.

Jane breathed fast with excitement. The laundress’ slip of the tongue, after denying that she understood, was evidence in itself of her deliberate duplicity. Realizing her mistake, the old woman now sullenly refused to answer any questions, merely shaking her head and trying to dodge past and escape.

To prolong the questioning, Jane felt, would be only to arouse suspicion, and reluctantly she allowed old Lena to precede her to the elevator, anticipating her, however, in ringing the bell, pressing the button four times as Dean had directed. As they descended together she was almost in a panic. How long had she kept the laundress on the roof? She really had no idea. She had been so absorbed in her new discovery she had given no thought to the time. For all she knew she might have been there only five minutes. Had Dean had time to finish his work?

Almost frenzied with anxiety, wondering if it were too soon, she moved forward in the car so as to obstruct old Lena’s view through the door as it opened. One glance showed her the Hoff door now tightly closed, and she thought she heard the door of her own apartment just closing. Suddenly she remembered that she had gone up on the roof without a key. It would be a pretty pass if Dean were still in the Hoff apartment and she couldn’t get into her own.

All in a tremble she pressed the button of her own door, waiting, however, to see that the laundress was out of the hall. It was Dean who opened the door, and she all but fainted in his arms as she saw that he was back in safety.

“It’s done,” he cried gleefully, as he caught her and drew her within, closing the door carefully behind her. “I just finished my work as you came down.”

Great drops of perspiration still stood on his forehead and he was breathing rapidly.

“Why, what’s the matter?” he cried, noticing for the first time Jane’s perturbation. “Was it too much for you? What happened?”

“Put this down quick, quick,” gasped Jane, “Red—two large—one small—one large—one small—and then—red—two small—one large—three small—two large.”

Wonderingly he complied, jotting down what she told him in his notebook, and turning to ask her what it meant, discovered that she had fainted.

CHAPTER VIII THE LISTENING EAR

“I don’t know what is the matter with Jane,” sighed Mrs. Strong a few days after the employment of the new chauffeur.

“She’s not ill, is she?” responded her husband. “I never saw her looking more fit.”

“She looks all right,” said her mother. “It is the peculiar way she is acting that bothers me. She spends hours and hours moping in her room, and then there are times when she takes notions of going out and is positively insistent that she must have the car.”

“Maybe she’s in love,” suggested Mr. Strong, resorting to the common masculine suspicion.

“With whom?” retorted his wife indignantly. “I don’t believe there is an eligible man under forty in all New York. None of the men are thinking about marriage these days. They all want to go to France, even the married ones. I believe you’d go yourself if you were a few years younger.”

“I certainly would,” announced her husband enthusiastically.

“Jane tells me she is writing a novel,” Mrs. Strong continued, “and that’s why she stays in her room so much. I hope she won’t turn out to be literary.”

“Don’t worry,” advised Mr. Strong. “With all the men off to war you’ll find young women doing all kinds of funny things to work off their energy. If a girl can’t be husband-hunting, she’s got to be doing something to keep busy. There are worse things than trying to write novels. Jane is all right. Let her alone.”

So, even though her mother’s suspicions had been aroused, the girl in the next few days managed to spend many hours with her ears glued to the receiver of the dictograph without being discovered. In the Hoffs’ apartment Dean had succeeded in locating it over the dining-room table, concealed in the chandelier, and in Jane’s room the other end rested in the back of a dresser drawer that she always carefully locked when absent.

The novelty of listening for bits of her neighbors’ conversation quickly wore off. To sit almost motionless for hours listening, listening intently for every sound, hearing occasional words spoken either in too low tones or too far distant to make them understandable, to record bits of conversation that sounded harmless, yet might have some sinister meaning, became a most laborious task. Yet persistently Jane stuck at it. The greater knowledge she gained of the plottings of the German agents, the more important and vital she realized it was for every clue to be diligently followed in the hope that the trail might at last reach the master-spy, whose manifold activities were menacing America.

In general she was disappointed with the results of her listening. To be sure they had furnished indisputable evidence of something they already had ascertained—that old Hoff, despite being a naturalized American, still was a devoted adherent of the ruler of Germany. Nightly as he and his nephew sat down to dinner she could hear his gruff, unpleasant voice ceremoniously proposing always the same toast:

“Der Kaiser!”

Even when the younger Hoff was dining out, as he sometimes did, Jane could hear the old man giving the toast, presumably with only the old servant for an auditor. That the woman, too, was a spy, as well as servant, Jane had known since the day on the roof, but so far neither she nor Dean had been able to make anything out of her handkerchief code, though both were sure the messages related to the sailings of transports.

Only once had she heard anything that she deemed really important. One evening, as uncle and nephew dined, there had been an acrimonious dispute.

“Have you it yet?” the uncle had asked in German.

“Not yet,” Frederic had answered.

His seemingly simple reply for some reason appeared to have stirred the elder man’s wrath. He broke into a volley of curses and epithets, reproaching his nephew for his delay. In the rapid medley of oaths and expostulations Jane could distinguish only occasional words—“afraid”—“haste”—”all-highest importance”—“American swine.” The younger Hoff had appeared to exercise marvelous self-control.

“There is yet time,” he answered calmly.

“Donnerwetter,” the old man had exclaimed. “There is yet time, you say—and Emil the wonder-worker almost ready has. It must be done at once.”

The outburst over, old Hoff had subsided into inarticulate mutterings, evidently busy with his food, leaving Jane to wonder futilely who Emil might be, what he meant by the “wonder-worker,” and what particular task had been assigned to the nephew that must be performed immediately. She had hastened to report this conversation in detail to Chief Fleck, but if he understood what it was about he had taken neither Jane nor Thomas Dean into his confidence.

Other things, too, Jane had learned and reported, which she knew the chief appreciated even though he was sparing in his thanks and compliments. She had learned through her almost constant listening that Lieutenant Kramer was a regular visitor, coming to the Hoff apartment or seeing Frederic Hoff somewhere every other day. Unfortunately he was always conducted into one of the inner rooms, so that no more of the conversation than the ordinary greetings and farewells ever reached Jane’s ears. The mere fact of his coming so regularly to the Hoffs convicted him of treachery, in Jane’s mind. What proper business could an American naval officer have in the home of two German agents? The excuse that Frederic Hoff was a delightful and entertaining friend was entirely too flimsy and unsatisfactory.

Nothing that she had overheard—and within her heart she felt glad that it was so—in any way as yet incriminated young Hoff. When she dared to think about it, she found herself almost believing, certainly at least wishing, that the nephew was not involved in his uncle’s activities. Most of his time, in fact, was spent out of the apartment. He frequently went out early in the morning, not returning until the early hours of the next morning. The old man, on the contrary, always stayed at home until eleven o’clock. At that hour his telephone would ring. The telephone was located near the dining room, so Jane could easily hear his conversations. Invariably some brief message was given to him, a name, which he repeated aloud as if for verification.

As Jane overheard them she had set them down:

Thursday—“Jones.”
Friday—“Simpson.”
Saturday—“Marks.”
Sunday—“Heilwitz.”
Monday—“Lilienthal.”
Tuesday—“Wheeler.”

As she sat by the hour listening Jane kept pondering over these names. What could they mean? Were they, too, a code of some sort? Always, as soon as this word had come to him, old Hoff went out. Could they be, she wondered, passwords by which he gained access somewhere to government buildings or places where munitions were being made or shipped?

Meanwhile her acquaintance with Frederic Hoff had been progressing rapidly. As she had suggested he had called on her and had been presented to her father, and on the next Saturday they had gone to a matinée together. She had been eager to see what her father thought of him, for Mr. Strong, she knew, was regarded as a shrewd judge of men.

“What does that young Hoff do who was here last night?” her father had asked at the breakfast table.

“He’s in the importing business with his uncle, I think,” she had answered.

“Where’d you meet him?”

“He lives in the apartment next door. Lieutenant Kramer introduced him.”

“He’s German, isn’t he?”

“Oh, no,” said Jane, almost unconsciously rallying to defend him, “he was born in this country.”

“Well, it’s a German name.”

“Don’t you like him?”

“He talks well,” her father said, “and seems to be well-bred.”

It was with reluctance, too, that Jane admitted to herself that the better acquainted she became with Frederic Hoff the more fascinating she found his society. She was always expecting that by some word or action he would reveal to her his true character. At the matinée she had waited anxiously to see what he would do when the orchestra played the national anthem. To her amazement he was on his feet almost among the first and remained standing in an attitude of the utmost respect until the last bar was completed. If he were only pretending the rôle of a good American, he certainly was a wonderful actor. As her admiration for him increased and her interest in him grew she found that almost her only antidote was to try to keep thinking of his face as she had seen it the night that K-19—the other K-19—had been so mysteriously murdered. She kept wondering if Chief Fleck had made any further discoveries about the murder and resolved to ask him about it at the first opportunity. She therefore was delighted when on Tuesday, as she made her regular report by telephone, he asked if she could come to his office that afternoon with Dean to discuss some matters of importance. They found Carter already with the chief when they arrived.

“Thanks to your work, Miss Strong, and to Dean’s dictograph,” said the chief, “we have made considerable progress. We have learned a lot more about the cipher messages.”

“You have learned it through me,” cried Jane in amazement.

“Yes,” said the chief, smiling, “from that list of names you reported.”

“What were they, a cipher, a code?” questioned the girl breathlessly.

“No, nothing like that. They are merely the names of various innocent and unsuspecting booksellers in various parts of the city.”

“How did you discover that?”

“In the simplest and easiest way possible. I listed all the names you reported and studied them carefully, trying to find their common denominator. They were not in the same neighborhood, so it was not locality. They were not all German, so it was not racial. I looked them up in the telephone directory, checking up the numbers of the telephones of the Jones, the Simpsons, but that gave no clue. Then, as I looked through the telephone lists, I discovered that there was a bookstore kept by a man of each name. Then I understood. It is a simple plan for throwing off shadowers.”

“You mean that Mr. Hoff goes to a different bookstore each day to leave a code message?”

“That’s it. The spy who gets the messages each morning calls him up by ’phone, mentioning just the one word. From that Mr. Hoff knows just where to go, concealing the message in a book before agreed upon.”

“The fifth book,” interrupted Dean.

“Not always,” explained Fleck. “It depends on whether there are five letters in the name telephoned. I have located and copied several more of the messages.”

“But who gets the messages he leaves? Who takes them away from the bookshops?” asked Jane, mindful of her own failure in that respect.

“It’s a girl, or rather two girls together, though possibly only one of them is in the plot. Very likely the other may not know what her companion is doing.”

“To whom does this girl take them?”

“That is still a mystery,” said the chief. “We have ascertained who the girl is, where she lives. Her actions have been watched and recorded for every hour in the twenty-four for the last three days, and yet we don’t know what she does with these messages. Carter has a theory—tell us about it, Carter.”

“In accordance with instructions,” began Carter, as if he was making out a report, “I had operatives K-24 and K-11 shadow the party suspected. On two different occasions they followed her to a bookstore and back home again. She was accompanied on one occasion by her younger sister. Each time she went directly home and stopped there, neither she nor her sister coming out again, and no person visiting the apartment, but—”

“Here’s the interesting part,” interrupted Fleck.

“On both occasions within a couple of blocks of the bookstore she passed a man with a dachshund. She did not speak to the man, but each time she stopped to pet the dog.”

“Was it the same man both times?” asked Dean.

“Apparently not,” replied Carter, “but it may have been the same dog. Dachshunds all look alike.”

“Go on,” said the chief.

“Now my theory is that that girl was instructed to walk north until she met the man with the dog. I’ll bet anything that code message went under the dog’s collar. The next time she gets a message I’m going to get that dog.”

“It seems preposterous,” scoffed Dean.

“Rather it shows,” said Fleck, “that these spies all suspect they are being watched, and that they resort to the most extraordinary methods of communication to throw off shadowers. They have used dachshunds before. There’s a New England munition plant to which they used to send a messenger each week to learn how their plans for strikes and destruction were progressing. They put a different man on the job each time to avoid stirring up suspicion. At the station there would always be two children playing with a dachshund. The spy would simply follow them as if casually, and they would lead him to a rendezvous with the local plotters. Now, Miss Strong,” he said, turning to Jane, “I brought you down here for two reasons. First, to give you an inkling of how important your task is, and second, to ask you to undertake still another task for us. Are you still willing to help?”

“More than ever,” said the girl firmly.

“The one disappointment is that we are getting no evidence whatever to involve or incriminate young Hoff. To-morrow, while he and his uncle are away on their usual auto trip, I am going to have the apartment thoroughly searched.”

Jane’s face blanched. She recalled what a strain it had been on her nerves the day she watched on the roof while Dean installed the dictograph. She felt hardly equal to the task of ransacking desks and drawers.

“There will be no one at home but the old servant. She can be easily disposed of. It is imperative that the search be made at once. There is evidence that what they are planning—evidently some big coup—is nearing the time for its execution. We must find it out in order to thwart them. I have got to know what old Hoff meant by the ‘wonder-worker!’ He said that it was nearly ready. I suspect that it is some new engine of destruction. We must prevent any disaster to transports or munition factories, if that’s what they have in mind.”

“You think it’s a bomb plot?” asked Jane.

“I don’t know what it is. These empire-mad fools stop at nothing. Nothing is sacred to them, women, children, property. With fanatical energy and ability they commit murders, resort to arson, use poisons, foment strikes, wreck buildings, blow up ships, do anything, attempt anything to serve the Kaiser. Karl Boy-ed spent three millions here in America in two months, and Von Papen a million more. What for? Ten thousand dollars to one man to start a bomb factory, twenty-five thousand dollars to another to blow up a tunnel. Millions on millions for German propaganda was raised right here, and it is far from all spent yet. We’ve got to find out what the wonder-worker is and destroy it before it destroys—God knows what.”

“Very well,” said Jane with quiet determination, “I’ll search their apartment.”

“No, not that,” said the chief, “I’ll send some fake inspectors to test the electric wiring, and they’ll do the searching. I do not know for sure that the Hoffs suspect you of watching them, but I’m taking no chances. It will be just as well for you and Dean to be out of the way to-morrow all day, so that you will have an alibi. Germany’s secret agents are suspicious of everybody. They do not even trust their own people. What I want you and Dean to do is to try to follow the Hoffs and see where they go. I don’t want to use the same persons twice to trail them as they may get suspicious.”

“I can easily do that,” said Jane, feeling relieved. “I’ll tell Mother I want our car for all day.”

“No, don’t use your own car. They might recognize it. I’ll provide another one. They gave two of my men the slip last week somewhere the other side of Tarrytown. Let’s hope they are not so successful this time.”

“But won’t they recognize me?”

“Not if you disguise yourself with goggles and a dust coat. Dean can make up, too. He had practice enough at college, eh, Dean?”

Jane turned to look interestedly at Dean, who had the grace to color up. She was right then. He was a college man, working in the secret service not for the sake of the job but for the sake of his country.

“Of course I can disguise myself too,” she said enthusiastically, a new zest in her work asserting itself, now that she knew her principal co-operator was probably in the same social stratum as herself.

“You can rely on us, Chief,” said Dean, as they left the office together. “We’ll run them down.”

As they emerged into Broadway and turned north to reach the subway at Fulton Street, Dean, with a warning “sst,” suddenly caught Jane’s arm and drew her to a shop window, where he appeared to be pointing out some goods displayed there. As he did so he whispered:

“Don’t say a word and don’t turn around, but watch the people passing, in this mirror here—quick, now, look.”

Jane, as she was bidden, glanced, at first curiously and then in recognition and amazement, at a tall figure reflected in the mirror, as he passed close behind her. It was a man in uniform. Regardless of Dean’s warning she turned abruptly to stare uncertainly at the military back now a few paces away.

“Did you recognize him?” cried Dean.

“It—it looked like Frederic Hoff,” faltered the girl.

“It was Frederic Hoff,” corrected her companion, “Frederic Hoff in the uniform of a British officer, a British cavalry captain!”

CHAPTER IX THE PURSUIT

Masked by an enormous pair of motor goggles and further shielded from recognition by a cap drawn down almost over his nose, Thomas Dean in a basket-rigged motorcycle impatiently sat awaiting the arrival of Jane Strong at a corner they had agreed upon the evening before. He had been particularly insistent that Jane should be on hand at a quarter before eight. He had learned by judicious inquiries that always on Wednesdays—at least on the Wednesdays previous—the Hoffs had started off on their mysterious trips at eight sharp. His intention was to get away ahead of them and pick them up somewhere outside the city limits.

Jane had promised that she would be on hand promptly. Once more he looked impatiently at his watch. It lacked just half a minute of the quarter, but there was no sign of his fellow operative. The only person visible in the block was a boy strolling carelessly in his direction. With a muttered exclamation of annoyance Dean restored his watch to his pocket, debating with himself how long he ought to wait and whether or not he had better wait if she did not appear soon. Very possibly, he realized, something entirely unforeseen might have detained her or have prevented her coming. Perhaps her family had doubted her story that she was going off on an all-day motor trip with a friend? Maybe their suspicions had been aroused by his having reported sick? He had almost decided to go on alone when he observed that the boy he had seen approaching was standing beside the motorcycle.

“Good morning, Thomas,” said the boy, a little doubtfully, as if not quite sure that it was he.

Dean gasped in astonishment. The boy’s voice was the voice of Jane. Laughing merrily at his amazement and discomfiture, she climbed into the seat beside him, asking:

“How do you like my disguise?”

“It’s great,” he cried. “You fooled me completely, and I was expecting you.”

“When Chief Fleck said I ought to disguise myself for fear that the Hoffs already suspected me, I happened to remember these clothes. I had them once for a play we gave in school.”

“But you don’t even walk like a girl.”

Jane laughed again.

“I practised that walk for days and days. When I first put on this suit my brother hooted at the way I walked. He said no girl ever could learn to walk like a boy. I made up my mind I’d show him.”

“But your hair,” protested Dean, almost anxiously. Even if he was just now assuming the humble rôle of chauffeur he still was an ardent admirer of such hair as Jane’s, long, black and luxurious.

“Tucked up under my cap,” laughed the girl, “and for fear it might tumble down, I brought this along. It’s what the sailor boys call a ‘beanie,’ isn’t it?”

As she spoke she adjusted over her head a visorlike woolen cap that left only her face showing.

“But your mother—didn’t she wonder about your wearing those clothes?”

“She was in bed when I left. All she caught was just a glimpse of me in Dad’s dust coat, and that came to my ankles. I wore it until I was a block away from the house. Will I do?”

“You can’t change your eyes,” said Dean boldly, that is boldly for a chauffeur, but he knew that Jane knew he wasn’t a chauffeur except by choice, so that made it all right.

“I couldn’t well leave them behind. I understood that I was to have a lot of use for my eyes to-day.”

“Yes, indeed, you very likely will.”

“Do you know I hardly recognized you at first and was almost afraid to speak? I had expected to find you in a car. What was the idea of the motorcycle?”

“It was Chief Fleck’s suggestion. The Hoffs will be motoring. People in a car seldom pay any attention to motorcyclists. If we were to follow them in a motor they’d surely notice it. Last week they managed to dodge the people the Chief assigned to trail them. Maybe as two dusty motorcyclists we’ll have better luck.”

“I hope so. Where do you intend waiting to pick them up?”

“Getty Square in Yonkers is the best place. Everybody going north goes that way. I can be tinkering with the machine while you keep watch for them. They will not be apt to suspect a pair of Yonkers motorcyclists. There’s no danger of missing them.”

“Did you tell the Chief about seeing Mr. Hoff in that uniform?”

“Of course. He did not seem even surprised. Some one had reported to him already that there was a German going about in British uniform.”

“What had he heard? What was the man doing?” questioned Jane anxiously. Even though she believed Frederic Hoff an alien enemy, even though she was all but sure that he was a murderer, she kept finding herself always hoping for something in his favor. He seemed far too nice and entertaining to be engaged in any nefarious, underhanded, despicable machinations. Yet she had seen him masquerading as a British officer. She could not doubt the evidence of her own eyes.

“What happened was this,” continued Dean. “A woman—one of the society lot—was driving down Park Avenue day before yesterday morning in her motor. It had been raining, and the streets were muddy. At one of the crossings a British officer stopped to let the car pass. One of the wheels hit a rut, and his uniform was all splashed with mud. He burst into a string of curses—German curses.”

“He cursed in German?” cried Jane.

“Sure,” said Dean. “On the impulse of the moment he forgot his rôle and revealed his true self—an arrogant Prussian officer.”

“What did the woman do?”

“Reported him to the first policeman she met, but by that time he had vanished, of course.”

“What did Chief Fleck think about it?”

“He didn’t seem to take the story seriously.”

“Do you suppose it could have been Mr. Hoff?”

“It must have been he, or one of his gang, at any rate. I don’t see why the Chief does not order his arrest at once. He is far too dangerous to be at large.”

“There’s no real evidence against him yet,” protested Jane, “not against the young man, at least.”

“Didn’t we both see him in British uniform?”

“Yes,” admitted the girl.

“Well, that’s proof, isn’t it? A man with a German name in British uniform in wartime can’t be up to any good.”

“Still we have no actual evidence against him. We don’t know what he was doing.”

“I’d arrest him then for murder and get the evidence that he is a spy afterward. It would be easy to fasten the murder of K-19 on him. There’s no doubt that he did that.”

“Has a witness been found?” asked Jane with a quick catch of the breath. Somehow she never had been able to persuade herself that the man next door, whatever else he might be, had really committed that brutal murder.

“No, there’s no actual witness, but it could be proved by circumstantial evidence. K-19, the man whose work you took up, had instructions to shadow young Hoff to his home. At two in the morning he relieved another operative. At three you yourself saw him shadowing Hoff.”

“I saw two men on the sidewalk,” corrected Jane. “One of them was Frederic Hoff. I did not see the other distinctly enough to identify him. I saw no murder. I merely saw the two of them run around the corner.”

“Look here,” said Dean sharply, not wholly succeeding in suppressing a note of jealousy in his tones, “I believe you are trying to shield Frederic Hoff. What is he to you? Has he won you over to his side?”

“You’ve no right to say such things to me,” cried Jane, nevertheless coloring furiously. “I’ve seen the man only three or four times. I am working just as hard as you are to prove that he is a German spy, if he is one. I am only trying to be fair. I know nothing that convicts him of murder. Any testimony I could give would not prove a single thing.”

“Certainly not, if that’s the way you feel about it,” snapped Dean.

After that they rode along together in silence, each busy with thoughts of their own. Dean was cursing himself for having let his enthusiasm to be of service to his government lead him into such circumstances. He felt that his chauffeur’s position handicapped him in his relations with Jane, to whom he had been strongly attracted from the beginning. The son of a distinguished American diplomat, he had been educated for the most part in Europe. Friends of his father, when he had offered his services to the government, had convinced him that his knowledge of German and French would make him most useful in the secret service. Reluctantly he had consented to take up the work, and as he had gone further and further into it and had realized the vast machinery for surreptitious observation and dangerous activity that the German agents had secretly planted in the United States, he had become fascinated with his occupation—that is, until he met Jane Strong.

His association with her under present circumstances was fast becoming unbearable. Even though he was aware that she knew he was no ordinary chauffeur, he loathed the necessity of having to wear his mask in the presence of her family. He wanted to be free to come to see her, to send her flowers and to go about with her. For him to take any advantage of their present intimate relations to court her seemed to him little short of a betrayal of his government, yet at times it was all he could do to keep from telling her that he adored her. Love’s sharp instincts, too, had made him realize that Jane was already beginning to be attracted by the handsome young German whom they were seeking to entrap, and the knowledge of this fact filled him with helpless rage and jealousy.

Jane, too, angered and insulted at first by Dean’s outburst, had been endeavoring to analyze her own conduct. Candor reluctantly compelled her to admit that each time she met Frederic Hoff she had found herself coming more and more under his spell. He had a wonderful personality, talked entertainingly and ever exhibited an innate gallantry toward women in general, and herself in particular, which Jane had found delightfully interesting. Though she had undertaken wholeheartedly to try to get evidence against him, she was forced to admit to herself now that she was secretly delighted that there had been nothing damaging found as yet, so far as he was concerned, beyond the one fact that he had been in British uniform.

In vain she marshalled the circumstances about him, trying to make herself hate him. He was a German, she told herself. He was an enemy of her country. He lived with a man who had been proved to be a spy. He surreptitiously associated with American naval officers. The dictograph told her that nightly his uncle and he in the seclusion of their home toasted America’s arch enemy, the German Kaiser. More than likely, too, her reason told her, he was a murderer. She ought to hate, to loathe, to despise him, and yet she didn’t. She liked him. Whenever he approached she could feel her heart beating faster. She looked forward after each meeting with him to the time when she would see him again. What, she wondered, could be the matter with her? Assuredly she was a good patriotic American girl. Why couldn’t she hate Frederic Hoff as she knew he ought to be hated?

She was still puzzling over her unruly heart when they reached Getty Square, and Dean brought the motorcycle to a stop in one of the side streets overlooking Broadway. Dismounting, he looked at his watch and made a pretense of tinkering with the engine, while Jane kept a sharp lookout on the main thoroughfare, by which they expected the Hoffs to approach. Ten minutes, twenty minutes, more than half an hour they waited, anxiously scanning each car as it passed.

“I can’t understand it,” said Dean. “They should have been here at least twenty minutes ago. I am going to ’phone Carter. He will know what time they started.”

He had hardly entered an adjacent shop before Jane, still keeping watch, saw the Hoffs’ car flash by, going rapidly north. Quickly she sprang out and ran into the store. Dean saw her coming and left the telephone booth, his finger on his lips in a warning gesture.

“Don’t bother to ’phone,” cried the girl, misunderstanding his meaning—and thinking only that he was trying to prevent her naming the Hoffs. “Come, let’s get started.”

Without speaking he hurried from the store and got the motorcycle under way.

“Have they passed?” he whispered then.

“Just a moment ago.”

Silently he gathered up speed, racing in the direction the Hoffs’ car had gone, not addressing her again until perhaps two miles from Getty Square they caught up with it close enough to identify the occupants, whereupon he slowed down and followed at a more discreet interval.

“Be careful about speaking to me when there’s any one about,” he warned Jane, almost crossly. “Those clothes make you look like a boy, and your walk is all right, but your voice gives you away. Did you see that clerk in the store look at you when you spoke to me? I tried to warn you to say nothing.”

“I’ll be careful hereafter,” said Jane humbly, still depressed by her recent estimate of herself. “I forgot about my voice.”

Mile after mile they kept up the pursuit without further exchange of conversation. As they passed through various towns along the road Dean purposely lagged behind for fear of attracting attention, but always on the outskirts he raced until he caught up close enough again to the car to identify it, then let his motorcycle lag back again. Thus far the Hoffs had given no indication of any intention to leave the main road.

As the cyclists, far behind, came down a long winding hill on which they had managed to catch occasional glimpses of their quarry, Dean, with a muttered exclamation, put on a sudden burst of speed. At a rise in the road he had seen the Hoffs’ car swing sharply to the left. Furiously he negotiated the rest of the hill, arriving at the base just in time to see them boarding a little ferry the other side of the railroad tracks. While he and Jane were still five hundred yards away the ferryboat, with a warning toot, slipped slowly out into the Hudson.

In blank despair they turned to face each other. The situation seemed hopeless. They dared not shout or try to detain the boat. That surely would betray to the Hoffs that they were being followed. Despondently Dean clambered off the motorcycle and crossed to read a placard on the ferryhouse.

“There’s not another boat for half an hour,” he said when he returned. “They have gained that much on us.”

“Perhaps we can pick up their trail on the other side of the river,” suggested Jane. “There are not nearly so many cars passing as there would be in the city.”

“We can only try,” said Dean gloomily.

“At least we know where to pick up their trail the next time.”

“Damn them,” cried Dean, “I believe they suspect that they may be followed and time their arrival here so as to be the last aboard the ferryboat. That shuts off pursuit effectually. They make this trip every week. I wouldn’t be surprised if they have not fixed it with the ferry people to pull out as soon as they arrive. A two-dollar bill might do the trick. I’d give five thousand right now if we were on the other side of the river. It’s the first time—the only time I’ve ever failed the Chief.”

“Never mind,” said Jane consolingly, “why can’t we be waiting for them at the other side next week when they come up here? They’re not apt to suspect motorcyclists they meet up here with having followed them.”

“Perhaps next week will be too late.”

“I wonder where they are headed for,” said the girl, looking across at the rapidly receding boat. “Why, look! What are those buildings over there?”

“That’s West Point,” Dean exclaimed, noting for the first time where they were.

“West Point!” she echoed in amazement.

What mission could the Hoffs have that would take them to the United States Government military school was the question that perplexed them both. Could it be that the web of treachery and destruction the Kaiser’s busy agents were weaving had its deadly strands fastened even here—at West Point?

CHAPTER X CARTER’S DISCOVERY

“It’s the young man I’m after,” said Chief Fleck. “We have the goods on old Hoff, but we have nothing incriminating against Frederic yet. The very fact that he holds aloof from his uncle’s activities makes me think he is engaged in more important work. He’s just the type the Germans would select as a director.”

“That’s right,” said Carter despondently. “There’s nothing except the fact that Dean and the girl think they saw him in British uniform. Why didn’t they follow and make sure?”

“They tried to,” said the chief, “but he gave them the slip. I’m inclined to believe they were mistaken. More than likely it was a chance resemblance. Lots of Britishers of the Anglo-Saxon strain look much like Germans, and a uniform makes a big difference in a man’s appearance. I’m afraid there’s nothing in that.”

“But both saw the man—Dean and Miss Strong,” protested Carter.

“The trouble is,” observed Fleck, “that Dean is getting infatuated with the girl. A young man in love is not a keen observer. Anything she thinks she has seen he’ll be ready to swear to. I hope the girl keeps her head. Lovers don’t make good detectives.”

“I have watched them together,” said Carter. “I’ll admit he’s struck on her, but I don’t think she cares a rap for him. She’s too keenly interested in Frederic Hoff.”

“What do you mean by that?” asked the chief sharply.

“You can depend on her all right. She’s patriotic through and through. She’s the kind that would do her duty, no matter what it cost her. All I meant is that Hoff’s the type that interests women. He’s got a way about him. The fact that he’s a spy, in peril most of the time, gives him a sort of halo. I never knew a daring young criminal yet that didn’t have some woman, and often several of them, ready to go the limit for him. All the same, I’m sure we can trust Miss Strong.”

“We’ve got to,” growled Fleck, “for the present at any rate. Is everything fixed for the search this afternoon? What have you done to get the superintendent out of the way? He’s not to be trusted. His name is Hauser.”

“I’ve got him fixed. Jimmy Golden, my nephew, who has helped us in a couple of cases, is a lawyer. He has telephoned to Hauser to come to his office this afternoon.”

“Suppose he doesn’t go?”

“He’ll go all right. Jimmy ’phoned him that it was about a legacy. That’s sure bait. Jimmy will make Hauser wait an hour, then keep him talking half an hour longer. That will give us plenty of time.”

“Then there’s the woman—the servant, Lena Kraus.”

“She goes to the roof every Wednesday while the Hoffs are away to signal. Other days they apparently do the signalling themselves in some way we haven’t caught on to yet. She always goes up about three o’clock and—”

“Suppose she comes down unexpectedly and catches you? We can’t have that happen. That would put them on their guard.”

“She won’t surprise us. I’ve got a trick up my sleeve for preventing that.”

“Go to it, then,” said the chief, and Carter went on his way rejoicing.

Ever since he had been informed that the search of the Hoffs’ apartment was to be intrusted to him Carter had been in a state of exuberant delight. He fairly revelled in jobs that required a disguise and he welcomed the opportunity it gave him and his assistants to don the uniform of employees of the electric light company. He even made a point of arriving that afternoon at the apartment house in the company’s repair wagon, the vehicle having been procured through Fleck’s assistance.

“There’s a dangerous short circuit somewhere in the house,” he announced to the superintendent’s wife.

“My husband isn’t here,” she answered unsuspectingly. “Do you know where the switch-boards are?”

“We can find them,” said Carter. “We’ll start at the top floor and work down.”

Always thorough in his methods of camouflage he actually did go through several apartments, making a pretense of inspecting switch-boards and wiring, all the while keeping watch for the time when old Lena went to the roof. The moment she had entered the elevator to ascend with her basket of linen, Carter and his aides were at the Hoff door. Equipped with the key Dean had manufactured they had no difficulty in entering.

“Bob,” said Carter to one of his men, “we haven’t much time, and there’s a lot to be done. You take the servant’s room and the kitchen, and you, Williams, take the old man’s quarters. I’ll take care of the young man’s bedroom, and we’ll tackle the living room and dining room later.”

Thoroughly experienced in this sort of work all three of them set at once to their tasks. Carter, standing for a moment in the doorway, surveyed Frederic Hoff’s quarters, taking in all the details of the furnishings. Both the sitting room and the bedroom adjoining were equipped in military simplicity, with hardly an extra article of furniture or adornment, chairs, tables, everything of the plainest sort. Moving first into the bedroom, Carter quickly investigated pillows and mattress, but in neither place did he find what he sought, evidence of a secret hiding place. He rummaged for a while through the drawers of two tables, carefully restoring the contents, but discovering nothing that aroused his suspicions. The books lying about on the tables and on shelves he examined one by one, noting their titles, examining their bindings for hidden pockets, holding them up by their backs and shaking the leaves. There was nothing there. Lifting the rugs and moving the furniture about he made a careful survey of the flooring, seeking to find some panel that might conceal a hiding place. Once or twice in corners he went so far as to make soundings but apparently the whole floor was intact. His search in the bath room was equally profitless, and at last he turned to the clothes press. As he opened the door an exclamation of amazement burst from his lips.

There, concealed behind some other suits, was the complete outfit of a British cavalry captain.

“That’s one on the Chief,” he said to himself. “It must have been Hoff that Dean and Miss Strong saw. I wonder where he got it?”

With a grim smile of satisfaction he devoted himself to going carefully through all the pockets and over all the seams of the clothing in the closet. He even felt into the toe of the shoes and examined the soles. There was nothing to be found anywhere, but he felt satisfied. The uniform in itself was to his mind damning proof of the young man’s occupation.

No explanation that could be given by a young man of German name, even though he was American-born, or had an American birth certificate, could possibly account for his having a British uniform. It was prima facie evidence that Frederic Hoff was a spy. What puzzled Carter most was how Hoff managed to smuggle the uniform in and out of the apartment without being observed. For more than two weeks now every parcel that had arrived at the house of the Hoffs had been searched before it was delivered. The house had been constantly under the strictest surveillance. It was out of the question for him to have worn the uniform in or out as it could not be easily concealed under other clothing.

“There’s somebody else in this place in league with the Hoffs,” he muttered to himself. “I wonder who it can be.”

He looked at his watch. The old servant had been out now nearly half an hour. She was likely to return at any moment. He must work quickly. Swiftly he went through the dresser drawers but without satisfactory result. There was no time for him to do more. He hastened into the living room and summoned his aides.

“Find anything, Bob?” he asked.

“Not a thing.”

“Beat it up to the roof,” he directed. “Have you those field glasses with you?”

“Sure,” replied the operative, “and the handkerchiefs, too.”

“All right. Get up there before she starts down. Begin putting up handkerchiefs and appear to be watching the river. That will mix her up so she will not know what to do. She will not dare to leave the roof while you are there. When we’re through I’ll send the elevator man up for you with the message that we have found the short circuit.”

He turned to the other operative.

“Find anything, Williams?”

“Only this.”

Carter’s face brightened as his assistant held out to him two copies of an afternoon newspaper. In each of them a square was missing where something had been cut out.

“I found them in the waste-paper basket by the old man’s desk,” the man explained, “and there was some ashes there—ashes of paper—as if he had burned up something. Maybe it was what he cut out of those papers. I could not tell.”

“We’ve got to get copies of those papers at once and see what it was. Come on, I’m going to take them to the Chief. We can get the papers on the way down.”

Calling the other operative from the roof, before he even had had time to attract the attention of Lena Kraus by his activities, they hastened back to the office, where Fleck and Carter together scanned the two papers from which the clippings had been taken.

“Why,” said Carter disappointedly, “it is just a couple of advertisements he cut out—advertisements for a tooth paste. There’s nothing in that.”

“Don’t be too sure,” warned Fleck. “If a man cuts out one tooth-paste advertisement, the natural presumption would be that he wished to remind himself to buy some. When he cuts out two, he must have some special interest in that particular tooth paste. We’ll have to find out what his interest is.”

“Maybe he owns it,” suggested Carter.

“Perhaps,” said Fleck, as he began studying the advertisements, “but it would not surprise me if these advertisements contained some sort of code messages.”

“Messages in advertisements,” exclaimed Carter incredulously.

“Why not? The Germans have hundreds of spies at work here in this city and all over the country. What would be an easier method of communicating orders to them than by code messages concealed in advertising. They have done it before. When the German armies got into France they found their way placarded in advance with much useful information in harmless looking posters advertising a certain brand of chocolate. I’d be willing to bet that every one of these advertisements carries a code message. I’ve noticed that these advertisements, all peculiarly worded, have been running for some time. I never thought of hooking them up with German propaganda, but, see, it is a German firm that inserts them.”

Carefully he cut out the two advertisements and laid them side by side on his desk. Turning to Carter he said:

“Go at once to see Mr. Sprague, the publisher of this paper. Get him to give you a copy of each paper that has contained an advertisement of this sort in the last six months. Find out what agency places the advertising. Tell him I want to know. He’ll understand. We have worked together before.”

Alone in his office, Fleck bent with wrinkled brow over the first of the two advertisements, which read:

REMEMBER

Please, that our new paste, DENTO,
will stop decay of your teeth. Sound
teeth are passports to good health and
comfort. Now, no business man can
risk ill health. It is closely allied with
failure. The teeth if not watched are
quickly gone.

USE DENTO

A genuine, safe, pleasing paste for the
teeth, prepared and sold only by the
Auer Dental Company, New York.

He tried all the methods of solving cipher letters that he thought of. He drew diagonals this way and that across the advertisement. He tried reading it backward. He tried reading every other word, every third word, both backward and forward. Nothing that he did revealed any combination of words that made sense.

“Passports,” he muttered to himself, “that’s it. If there is a message there it must be something about passports.”

In despair he turned to the other advertisement. It read:

DON’T

Forget it is imperative for one and all to
use cleansing agents on teeth that leave
no bad results.

“Ship more of that wonder-working
paste immediately. Workers, employers,
wives, all ready to commend it. Friday’s
supply gone,” writes a druggist to whom
a big shipment was made last week.

USE DENTO

A genuine, safe, pleasing paste for the
teeth, prepared and sold only by the
Auer Dental Company, New York.

Fleck’s eyes gleamed with satisfaction as he read this advertisement and caught the phrase “wonder-working.” He felt sure now that he was on the right track. He recalled that Jane Strong over the dictograph had heard old Hoff speak of something that he called the “wonder-worker.” As soon as Carter returned with the other advertisements that had been appearing he felt positive that he would be able to unravel the cipher. Two words he was sure of—“passports” and “wonder-working.” One footprint does not lead anywhere, but two do, and given three footprints, a pathway is indicated.

His telephone rang sharply. He turned to answer it, suspecting it must be Carter with some message about the papers he had sent for.

“Hello,” he called.

“Hello,” came a faint voice, as if the speaker were using long distance, and had a bad connection, “is this Fleck?”

“Yes, Fleck,” he answered, “who is this?”

“Dean speaking,” came the voice faintly.

“Dean,” cried Fleck, excitedly, “yes, yes. What is it, Dean?”

He had not expected to hear any results from the expedition that Dean and Jane Strong had undertaken until late in the afternoon after the Hoffs returned. The fact that Dean was calling him up now would seem to indicate that something of importance had happened.

“I’m telephoning from a doctor’s house near Nyack,” said Dean.

“What’s that? Speak louder.”

“I’m here in Doctor Spencer’s office near Nyack with a broken arm,” Dean continued. “We’ve had an accident. Somebody’s auto smashed into us, I guess.”

“Miss Strong? Where is she? Is she hurt?” asked the chief anxiously.

“I don’t know. She has vanished.”

Jane Strong vanished! The chief’s figure became suddenly tensed. That it was more than a mere automobile accident he felt certain now. Shadowing the Hoffs was an occupation that seemed unusually perilous. There flashed into his mind the fate of K-19—murdered almost at the Hoffs’ door. And now two more of his operatives, one disabled and the other mysteriously missing.

“Quick,” he said over the ’phone. “Tell me briefly just what happened. Speak as loudly as you can.”

“We got half an hour behind at the West Point Ferry,” Dean’s voice went on, still weak and low as if he were speaking with difficulty. “We had some trouble getting started on the trail again but finally succeeded. We were dashing along about ten or twelve miles south of West Point when an automobile coming out of a cross road crashed right into us. It must have knocked me unconscious. I didn’t remember anything more till I found myself here. I came to as the doctor was setting my arm. I ’phoned as soon as they would let me.”

“Who brought you there?”

“I don’t know. All they know here was that some couple in an automobile left me here. They said they passed just after an auto hit my motorcycle. They said the auto didn’t stop.”

“And Miss Strong—did they say anything about her?”

“Not a word. The people here were under the impression I was riding alone.”

“All right,” said the chief. “I’ll get some one up there at once to look after you and pick up any clues.”

As he hung up the ’phone, his forehead wrinkled into little lines of absorbed concentration. He sat at his desk for fully five minutes almost motionless, trying to figure it out. What did the accident to Dean signify? How was the sudden disappearance of Jane Strong to be accounted for? Had she fled from the scene after Dean was disabled, fearing that her name might be coupled with his in an account of the accident? It did not seem like the sort of thing she would do. The impression she had made on him was that of a girl of high resolve who would be apt to carry through anything she undertook, cost what it may. Yet what could have happened to her? If she, too, had been injured, why was she not with Dean? If she was not injured, why had she not communicated with the office? Who were the couple that had brought Dean to the doctor’s office? Why had not the doctor taken their names and addresses?

What part had the Hoffs played in the accident? Had they purposely run down the motorcycle? If they had found out they were being shadowed they would not have hesitated, he felt sure, to resort to such murderous tactics. Had they not already one dastardly murder to their record? He must find out when the Hoffs arrived home. They would not be due for an hour or two, but he would caution the operatives watching the house to keep more vigilant watch. Reaching for his ’phone he called up the head-quarters of the operatives.

“Report to me at once,” he said to the operative who answered his call, “the minute the Hoffs have arrived home.”

“The old man is home now,” the operative answered.

“What’s that?” cried Fleck.

“He came in alone five minutes ago on foot. The young man is not home yet with the automobile.”

“Let me know as soon as he arrives,” said Fleck curtly, turning away from the ’phone.

He was more perplexed than ever. What could have happened? Where was young Hoff with the motor? Where was Jane Strong? Why had she disappeared after Dean had been hurt? How had she vanished? The Hoffs’ affairs had assuredly taken a new and bothersome turn, over which Fleck sat puzzling many minutes.

Where was Jane Strong? In the answer to that question, he decided at length, lay the crux of the whole situation.

CHAPTER XI JANE’S ADVENTURE

For more than two hours Thomas Dean and Jane had been vainly circling about West Point on their motorcycle, striving to pick up some clue that would put them once more on the trail of the Hoffs’ car. They had not dared to ask too many questions of any one near the ferry, fearful lest the people they were pursuing might have a guard posted there to warn them in case of a possible pursuit, yet cautious inquiries seemed to indicate that all the automobiles on the ferryboat which had preceded had been headed to the north.

“There’s only one thing we can do,” Dean had said despondently. “We have got to run out each road we come to until we reach some shop or garage where the people would be likely to have noticed the Hoffs. They may have stopped somewhere, or we may meet some one coming toward us who will remember having passed them.”

“It seems like a wild-goose chase,” said Jane, “but I suppose there is nothing else to do.”

The strain of their bitter disappointment was telling on both of them. Each felt inclined to blame the other for their having fallen so far behind. They rode along in silence, their nerves becoming more and more keyed up as their hopes grew less. At garage after garage they paused to question the employees.

“Did a big gray car with two men, an old man with a beard and a young man driving, pass this way about an hour ago?”

“I don’t remember any such car,” was the invariable answer.

Time and time again they repeated their query, wording it always the same, except for lengthening the interval of time in which the car might have passed, for the afternoon was rapidly passing. In their circuit they had now reached the roads pointing to the southward.

“We’ll try this one more garage,” said Dean, as they approached a wayside shed bearing a large sign “Gasoline.”

“I fear it is only wasting time,” said Jane wearily.

“Don’t you want the Hoffs caught?” snapped her companion.

“Of course I do,” she retorted heatedly, “but I don’t see you catching them.”

“I believe you are half glad of it,” snarled her escort as he brought the machine to a stop and repeated his usual question.

“Sure there was a car with two men in it like you describe passed here,” the man replied to their amazement and delight. “They stopped here for gas, as they generally do. About three hours ago, I guess it musta been.”

Dean shot a triumphant glance at Jane.

“An old man with a gray beard and a smooth-shaven young man driving—does that describe them?” he repeated.

“That’s them,” said the garage proprietor. “They come through here every few days, always about the same time.”

“Where do they go?” questioned Dean eagerly, feeling at last that the scent was growing hot.

The man shook his head in a puzzled way.

“I’ve often wondered about that. They’re always heading south and appear to be in a powerful hurry, but the funny part of it is I ain’t never seen them coming back.”

“Do you know their names?”

“No, I can’t say I do, though it seems as if I’d heard one of them called Fred. I can’t say which it was.”

“Do they always come by on the same day—on Wednesday?” asked Jane, forgetful once more of Dean’s warning to let him do the talking lest her voice should betray her sex.

“Come to think of it,” said the man, apparently noticing nothing unusual, “I guess it always is on a Wednesday they come by.”

“Is the number of their car anything like this?” asked Dean, exhibiting an entry in his notebook.

“I couldn’t say,” said the man, studying the figures. “I know it is a New York license, and the number ends with two nines like this one does. What might you be wanting them for?”

He spoke to a cloud of dust, for Dean had started up the motorcycle before he finished speaking and already was speeding away.

“Where now?” asked Jane.

“I don’t know,” he answered frankly, “I only know we are going the direction the Hoffs went, and I want to gain on them before they get too far ahead. The chap back there had told us all he knew and was beginning to get curious, so I thought it better to vamoose.”

“It’s funny about his never seeing them coming back.”

“Probably there is nothing mysterious about that. I have a notion they always come up one side the river and down the other, taking the 125th Street ferry home. That would not be a bad plan to help them in eluding too curious observers. All these German spies are trained to leave as blind a trail behind them as possible. The thing we have got to discover is what brought them up here. We’ve just got to find out their destination.”

“I am afraid there is little chance of our doing that,” insisted Jane. “We’ve nothing to go on.”

“We’ve learned something. We know that their destination is somewhere between here and Fort Lee on this side of the river. That narrows down the search considerably. That’s more, too, than anybody else that the Chief has had on their trail has learned. Something tells me that we are getting warm right now. Obviously the place they come to must be nearer West Point than it is New York. They would hardly take too roundabout a course, even for the sake of hiding their tracks. Keep a sharp lookout for tire tracks leaving the main road.”

The route they were following quickly led them into a sparsely inhabited mountainous district and instead of the concreted state highway they found themselves on a hilly dirt road, full of ruts and loose stones that made travel difficult. At times it was all Dean could do to manage the machine, so that he had to leave most of the task of observing the by-ways to Jane. For more than two miles they had seen neither house nor barn. Once or twice they came upon little used lanes leading off through the woods, but none of them showed any traces of the recent passing of an automobile.

As they came dashing around a curve on a steep down-grade, where hardly more than the semblance of a road had been cut into the hillside, Jane caught her breath sharply. Above the roar of their own motor she thought she heard some other noise, something that sounded like another car near-by; yet neither behind nor ahead was there another automobile in sight.

“Listen,” she cried sharply.

Dean started to slow down, but it was too late. Out of a cut in the hillside, half screened by a clump of bushes at the side on which Jane was riding, a great gray motor shot out just as they were passing. Jane caught just one glimpse of the man on the driver’s seat. It was Frederic Hoff, frantically twisting at the wheel in an effort to avert the threatened collision. There came a thud and a crash as the forward part of the Hoff car struck the motorcycle a glancing blow, overturning it completely. Too terrified even to shriek, Jane felt herself being catapulted out of her seat and flung high in air. Then came a blank.

Her companion did not escape so easily. The heavy machine crashed over on him and dragged him several yards. His head, as he landed in the roadway, struck a stone, and the motorcycle itself pinned him to the earth by its weight, one of his arms doubled up in an alarming fashion, as he lay there completely senseless.

Jane fortunately had landed on some soft grass, though with sufficient force to leave her badly stunned. As she lay there, a boyish figure in her disguise, her senses began gradually to revive, although it was some time before she opened her eyes.

Vaguely, as from a great distance, she began to hear voices, and it seemed to her that they were German voices, arguing about something. The voices seemed angry and excited. At first she did not bother about them. She was wondering how badly she was hurt. Her arms and limbs had a curious sort of deadness about them, a detached sensation, as if they belonged to some one else. She wondered if she was paralyzed and dared not try to move them, fearful lest she might find that it was the terrible truth.

The voices—the German voices—came nearer, became louder and more strident. She struggled to collect her thoughts. Where was she? What had happened? Where was Thomas Dean? Gradually some memory of the accident came to her. They had been run down by the Hoffs’ car. The voices she kept hearing were those of the two Hoffs, angrily wrangling about something. As she revived further she became acutely conscious that her head seemed to be splitting. What was it the Hoffs were arguing about? Still lying there motionless, with her eyes closed, endeavoring to collect herself, she tried to listen to what they were saying.

“I tell you there is not time. I must hurry. Every minute is precious. I cannot delay my work for these swine, no matter if they both are dying or dead,” old Otto was angrily shouting with many German oaths.

“I tell you,” Frederic was saying,—his voice was calmer but determined,—“we’ve got to get these people to a doctor. It’s too heartless. I will not leave them here.”

“And betray us at the last moment, when our plans are all ready,” snarled old Otto.

“There is less danger if we bundle them into the car and take them with us than if we leave them here,” protested Frederic. “Two bodies right here at the entrance would be fine, nicht wahr?”

His last remark appealed to old Otto.

“That is so,” he muttered. “It is not safe. We must hide the bodies, both of them, yes?”

The bodies! Jane decided that Dean must have been killed and that they thought that she, too, was dead. As she strove to open her eyes she could hear Frederic protesting.

“It’s inhuman,” he cried. “They both are hurt, but perhaps still alive. We must take them to a hospital.”

“And endanger all our plans,” stormed old Otto. “Throw them into the woods.”

“We’ll do nothing of the sort,” Frederic insisted, his voice becoming unusually stern and severe. “I’m going to get both of these people to a doctor at once, I tell you.”

With effort Jane opened her eyes and looked cautiously about. Where was Thomas Dean? How badly had he been hurt? The Hoffs’ automobile was slowly backing up. As she looked old Otto sprang out of it and righted the motorcycle. As he did so Jane saw the body of Dean lying senseless beneath it, but to him the old German paid no attention. He was examining the motorcycle and still sputtering that the swine should be left to rot.

“We are going to take them with us in the car,” directed Frederic in a voice of authority. “I command it.”

At the word old Otto’s mutterings ceased, though he shot a black look at the younger man.

“This machine,” he suggested, “it is not hurt. I will take it and do our work. There is haste. You remain with the car. Do what you will with these people.”

“Go then,” said his nephew curtly. “You can take the train at the first station and make time.”

As the old man mounted the motorcycle and sped away Frederic sprang from the car, and approaching the spot where Dean’s body lay, began making an examination of his injuries.

“Scalp wound, perhaps fractured skull, broken arm,” Jane heard him saying aloud to himself. She noted curiously that as soon as he was left to himself he began speaking in English.

He left Dean and approached her. As he came nearer she closed her eyes again, trying to plan some course of action. Her head was throbbing so that she found it impossible to think. She felt toward young Hoff a warmth of gratitude for not having gone off and left them helpless as his uncle had insisted. Even though he was an enemy of her country, a man to be hated, a spy, she could not help being glad for his presence there. What would she have done without him, with Dean lying there injured and helpless on this lonely mountain road?

“This chap seems only stunned,” she heard him say as he bent over her, then as he looked closer, she heard him exclaim:

“My God, it’s Jane!”

In an instant he was down at her side on his knees. Tenderly one of his arms went about her and lifted her head.

“Miss Strong, Jane, Jane,” he implored, “Jane dear, speak to me.”

“Thank God,” he cried. “Jane dear, tell me you are not hurt.”

Stunned though she still was a flush crept into Jane’s cheeks at the unexpected term of endearment, though she still kept her eyes closed. Gently he laid her back on the turf and hastened to the automobile, returning with a flask which he held to her lips. Slowly Jane opened her eyes.

“Thank God,” he cried. “Jane dear, tell me you are not hurt.”

For a moment she lay there, staring wonderingly at him as he bent over her imploringly, the tenderest of anxiety showing in every line of his face. Unprotestingly she let him slip his strong arm once more under her head. In her dazed brain there was a strange conflict of peculiar emotions. He was a German, a spy,—she hated him, and yet it was wonderfully comforting to her to have him there. Under other circumstances she could have loved him. He was so handsome, so masterful and so kind, too. He cared for her. Had he not called her “Jane, dear” in his amazement at finding her lying there? But she must not let herself think of him in that way. It was her duty, her sacred duty to trap him, to thwart his nefarious plans against her country. She must do her duty just as her soldier brother was doing his in far away France.

Still supported by Hoff’s arms she sat up, trying to collect her thoughts and gingerly testing the movement of her arms and limbs.

“Tell me,” he cried again, “Jane, dear, are you hurt?”

“I don’t think so,” she managed to say.

With his assistance she got up on her feet and walked uncertainly to the car, shuddering as she looked at Dean’s crumpled senseless body.

“Your friend,” said Hoff, as he placed her in the forward seat and wrapped a rug about her, “I am afraid, is badly hurt.”

“It’s our chauffeur, Thomas Dean,” she explained confusedly.

She had been wondering what she could say to Frederic to account for her presence there. It was unconventional at least for a girl to be motorcycling about the country dressed in man’s clothes with a chauffeur. Hoff must surely realize now that she had been shadowing him. She felt almost certain that he had known it from the very first, since that afternoon when he had overheard her telephoning about the “fifth book.” Yet never by word or manner had he betrayed the fact that he suspected her. Beyond his customary reserve in speaking about himself or his activities, there was nothing to indicate that he knew anything yet. Whatever she told him now she must be careful not to betray her mission. Perhaps even in spite of all that had happened she still might be able to aid Chief Fleck in trapping them.

But did she really want to trap Frederic Hoff? Had Thomas Dean’s bitter charge that she was trying to protect him been true? Frederic Hoff loved her. She, yes—she had to admit it to herself—she was beginning to love him. Could she go on with it?

Hoff had been busy lifting the unconscious Dean into the tonneau. As she watched him as he lifted up the body unaided she was conscious of admiration of his great strength.

“Will he die?” she whispered.

“I don’t know,” he answered. “He is badly hurt. We must get him to a doctor at once.”

He stopped a moment longer to examine the car. Fortunately the glancing blow that it had struck the motorcycle had done no more damage than shatter one of the lamps and bend the mud guard. Soon they were moving rapidly in the direction of New York.

“I think,” said Hoff, “we had better leave him in the care of the first doctor we come to. We can say that he is an injured motorcyclist we found lying in the road.”

“And me?” asked Jane, almost fearfully.

“I’ll take you back to the city with me.”

“No,” she replied, “that won’t do. I ought to stay by him. Besides, if I return with you, it will be hard to explain.”

He turned to look inquiringly at her and for a moment drove on in silence.

“There’s nothing more you can do for the man once he is in competent medical hands, except to notify his people. Is he married?”

“No,” said Jane, “he’s not married. I can tell his friends.”

“Did your parents know about”—he hesitated—“about this trip with the chauffeur?”

Jane blushed guiltily, wondering what he suspected of her. She hoped that he did not think she had a habit of going off on such journeys with the chauffeur. Even though the man at her side was officially her enemy she resented being put into a position that would cheapen her in his eyes.

“No,” she replied, “they knew nothing about it.”

Hoff drove on in silence. She had feared that he might ask her more embarrassing questions, might insist on knowing where she had been going when the accident occurred. A panic seized her. What if he should ask her? What could she tell him? He had a masterful way about him. If he took it into his head to make her confess she realized that she would have a struggle to keep from telling him everything. She made up her mind that she would not, she dare not answer any more questions.

When he spoke again she was relieved to hear a suggestion instead of a query.

“When we have crossed the ferry,” he said, “you can put on a dust coat to hide your costume, and I will send you home in a taxi. Will that be all right?”

“That will do nicely,” she replied, gratefully conscious that he was endeavoring to plan so that her part in the afternoon’s adventures need not become public.

Nevertheless she waited nervously while Hoff and the doctor carried Dean into the doctor’s home. What if the doctor’s suspicions should be aroused, and he should insist on knowing all the details of the accident? To her astonishment the doctor seemed to accept Hoff’s brief recital of finding an injured motorcyclist on the road without question. Perhaps if she had seen the amount of the bills Hoff left to care for the chauffeur’s treatment she might have understood better.

Yet unconscious though Dean had lain all the way, as they resumed their journey without him, she felt a sudden sense of dread at being alone in the car with Frederic Hoff. It was not that she longer feared he would endeavor to make her tell her reasons for the expedition. She was afraid that with just the two of them alone in the car he might seize the opportunity to declare his affection for her.

But, to her amazement, he hardly spoke a word to her on all the rest of the journey homeward. Once in a while as she ventured a glance in his direction, annoyed a little perhaps by this neglect of her, she saw only a strong face set in lines of thought, his brow wrinkled in deep perplexity, and his blue eyes looking steadily at the road ahead—and at something far, far beyond.

Save for an occasional solicitous question about her comfort he did not speak again until just after he had put her in a taxi at the ferry. As Jane was trying to say her thanks he leaned forward unexpectedly, his tall frame blocking the whole doorway.

“Jane,” he said, his voice vibrant with emotion, “Jane, you must trust me. Everything must come out all right. Some day—some day soon when we have won—I am coming to find you and tell you that I love you.”

“When we have won!” Jane shuddered and drew back in the car, aflame with sudden wrath.

She had read and had heard often of the unspeakable conceit of the Prussians. She knew that they regarded themselves as supermen who could not be defeated. Her challenged American pride rose to battle. As she rode home she was sure now that more than she hated anything else in the world she hated Frederic Hoff, the spy, the German, who had dared to boast to her that they expected to win.

CHAPTER XII PUZZLES AND PLANS

Chief Fleck had spent a sleepless night trying to put two and two together. Instead of the answer being “four” as it should have been each time he completed his figuring the result was “zero.” Time and again he mustered the facts into columns, only to succeed in puzzling himself the more.

Two German spies, the Hoffs, had set out together in their motor on their usual mysterious Wednesday mission. Two other persons, two of his most intelligent operatives, Thomas Dean and Jane Strong, had set out on a motorcycle to shadow them.

What had happened?

Otto Hoff had returned to his apartment on foot, hours before his usual time, seemingly much perturbed about something.

Frederic Hoff had arrived back at the apartment, also on foot, some hours later than usual, and the motor had not been returned to its usual garage. Frederic Hoff had appeared to be unusually elated about something.

Thomas Dean was in a doctor’s home somewhere up the Hudson with a broken arm and a bad scalp wound and was unable to tell what had become of either Miss Strong or the motorcycle.

Jane Strong had arrived home in a taxicab half an hour before Frederick Hoff, apparently unhurt but in a most peculiar condition of mind. When Chief Fleck had called her on the ’phone she had refused to answer any questions. The best he could get out of her was a promise that she would come to his office in the morning.

From this situation Fleck’s shrewd and experienced mind had been wholly unable to make any satisfactory deductions. That something unforeseen and unusual had happened to the Hoffs he was certain. It was the first time on a Wednesday that they had not returned together. Whatever it was that had happened it had depressed old Otto and had been a cause of elation to Frederic. What could it have been? That was the poser.

Coupled with this was the annoying fact of Jane Strong’s sudden reticence. Hitherto he had found her at all times ready and eager whenever he called on her—ready to do anything he asked her, or to tell him everything. Why had she suddenly balked? He recalled that Dean had hinted, and Carter, too, that the girl was becoming interested in the younger of the Germans, yet he scouted the possibility of Jane having gone over to the enemy’s side. A girl of her stock, living with her parents, with a brother fighting in France, never could be guilty of disloyalty, even if she were in love. Yet how was her disinclination to talk to be accounted for? After he had received a report that she was at home he had waited, expecting her to call him up. When she had not done so, he had called her. She had been positively curt and decisive. She had nothing to say to him, she had replied, at present. Dean was safe. She would come to his office in the morning. There was nothing for him to do but to await her arrival.

He was expecting Carter, too. He had sent him to Nyack the evening before as soon as he had learned of Dean’s whereabouts. Carter was to find out everything that Dean had learned and report as soon as he could. It was Carter who arrived first.

“Dean doesn’t know what happened to him, nor where the girl went,” said Carter. “They had lost the Hoffs’ trail at the Garrison ferry, as he told you over the ’phone. They had to wait there half an hour for another boat. They scouted around West Point, and nearly three hours afterward they picked up the trail heading toward New York. About ten miles south of West Point they were clipping along a mountain road when something happened. Dean is not sure whether he hit a stone in the road or whether an automobile struck them. He was knocked unconscious and didn’t remember anything more until he came to and found the doctor setting his arm.”

“Who took him to the doctor’s?”

“It was a couple, the doctor said, who explained that they had found Dean lying in the road under his wrecked motorcycle. The doctor could not remember what the couple looked like. Said he had been too busy looking after the injured man. I did worm out of him, though, that the man had left two hundred dollars with him to take care of Dean.”

“That’s funny,” said the chief.

“It sure is,” said Carter. “Looks like hush money to me. What does the girl say?”

“Nothing yet,” said Fleck. “She wouldn’t talk at all last night, but she’s coming here at ten.”

“That’s funny,” said Carter. “Why wouldn’t she talk?”

“I don’t know yet,” said Fleck decisively, “but I am going to find out. Do you really suppose that she has fallen in love with young Hoff?”

Carter shook his head.

“Dean thought so, and I know that Dean was in love with her himself, but I don’t know. I’d bank on that girl somehow, even if she is in love.”

“There she comes now,” said the chief as he heard the door of the outer office open.

As Jane entered she faced the two men almost defiantly. She too had had a sleepless night. Although she herself had been physically uninjured in the accident the shock to her nerves had left her unstrung, and besides she had been bothering all through the dark hours as to how much of what had happened in the last few hours it was her duty to tell to Chief Fleck.

As her personal relations with Frederic Hoff and her feelings toward him had in no way affected her sense of duty she felt that it was unnecessary for her to report the declaration of love he had made to her. Surely an affair that involved only the heart was her own property so long as she faithfully reported anything and everything that might lead to the exposure of the Hoffs’ plots. She could not see that it was any of Chief Fleck’s business, nor her country’s either, if Frederic Hoff had fallen in love with her. At any rate it would be utterly impossible for her to make any statement about her own feelings toward him. Even in her own heart and mind she was not quite sure what they were. From the first his forceful personality had had great charm for her. His obvious interest in her she had found delightful and flattering. When she recalled how gallantly he had insisted on remaining to rescue Dean and herself, even before he knew her identity, she was filled with admiration for him. Yet always matched against all that she found lovable in him was the knowledge that he was a German, a traitor, a spy, perhaps a murderer, and at times she felt that she hated him with a hatred that never could be overcome.

“Well,” said Fleck, studying her countenance, “what have you to tell us?”

“How is Dean?” she asked. “Will he live?”

Fleck and Carter exchanged glances. Was she, they wondered, really concerned in the handsome young chauffeur’s welfare, or had she merely put the question to gain time in framing what she was going to say?

“I just left him,” said Carter, in response to an almost imperceptible nod from the chief; “he’s all right except for a scalp wound and a broken arm.”

“I’m glad,” said the girl impulsively.

“What happened to him?” asked Carter.

“Don’t you know? The Hoffs’ automobile hit us and overturned the motorcycle.”

“The Hoffs’ car!” cried Fleck and Carter together.

“Yes, I thought you knew.”

“Tell us everything,” demanded Fleck. “Where did it happen? Did they run you down purposely?”

“I don’t think so; in fact I am sure they didn’t. It was entirely accidental.”

“Where did it happen? All Dean could remember was that you had picked up their trail about ten miles south of West Point. He could not tell how the accident occurred. He didn’t even mention the Hoffs or seem to suspect that they were anywhere near at the time.”

“I don’t think he saw their car at all,” Jane explained. “I caught just a glimpse of it before we were crashed into. We were on a mountain road going down a steep hill when their motor shot out of a deep cut just as we were passing.”

“What happened then?”

“I must have been stunned for a moment or two. When I regained my senses the Hoffs’ car had stopped, and Frederic was backing the car to where the accident had happened. His uncle was storming at him for stopping. He wanted Frederic to go on and leave us there, but Frederic wouldn’t do it, and they quarrelled. Frederic won out by pointing out that two bodies lying at the entrance would arouse suspicion.”

“At the entrance to what?”

“I don’t know. He didn’t say. I think I could find the place again.”

“We’ve got to find it,” said Carter.

“Indeed we have,” Jane agreed, “and quickly, too. I fear we are going to be too late. Old Mr. Hoff seemed to be in terrible haste and spoke of their plans being nearly completed.”

“Go on,” said Fleck quietly, “tell us the rest.”

“Frederic Hoff stayed behind to pick us up, and the old man went off on the motorcycle. I heard them talking about his taking a train at the nearest station.”

“What did young Hoff do when he found it was you lying there?”

“He seemed surprised and startled.”

“What did he say?”

Jane colored and hesitated. There rose in her mind the picture of his tall figure bending over her, with anguish in his eyes, with expressions of endearment on his lips. She could not, she would not tell them what he had said.

“He asked if I was hurt.”

“Is that all?”

Again she blushed and hesitated.

“That’s all.”

“Did he not seem amazed at finding you there? Did he not ask you to account for your presence there?”

“No,” said the girl, firmly, “he didn’t.”

“Didn’t he question you at all?”

“No,” she insisted, “he was busy getting Dean into the car. He was unconscious, and it looked as if he was badly hurt.”

“Queer, mighty queer,” muttered Carter to himself.

“Didn’t he ask you who Dean was?” questioned Fleck.

“I explained that he was our chauffeur. He may have known him by sight at any rate.”

“Go on.”

“We stopped at the house of the first doctor we came to and left Dean there, and then Mr. Hoff brought me on home in the car. At the ferry he put me into a taxi.”

“What did you talk about on the trip home?” asked Fleck suspiciously. “Didn’t he try to pump you?”

“We hardly talked at all. He seemed concerned only in getting me home without its becoming known that I had been in an accident.”

“Is that all?” asked the chief. She could see by his manner that he mistrusted her, that he felt that she was keeping something back.

“We hardly exchanged a dozen words,” she insisted.

Fleck shook his head in a puzzled way.

“I can’t understand it at all,” he said. “Old Otto is a common enough type of German, painstaking, methodical, stupid, stubborn, ready to commit any crime for Prussia, but the young fellow is of far different material. He has brains and daring and initiative. He is far more alert and more dangerous. I cannot understand his finding you there and not trying to discover what you were doing.”

“I can’t understand that either,” Jane admitted.

“There’s no doubt in my mind,” the chief continued, “that Frederic Hoff is the real conspirator, the head of the plotters.”

“Why do you say that?” asked Jane quickly. “What did you find out when you searched the apartment yesterday?”

She felt certain from the manner in which he spoke that he must now have some damning evidence of Frederic Hoff’s guilt. He was not in the habit of making decisions without proof.

“We found,” said Fleck, his keen eyes fixed on her face as if trying to read her innermost thoughts, “a British officer’s uniform hanging in Frederic Hoff’s closet, proof positive that he is a dangerous spy.”

“And,” said Carter, pointing to the two clippings lying on Fleck’s desk, “in the old man’s waste-paper basket we found those.”

Jane picked up the clippings and examined them curiously.

“What are they?” she asked, looking from one to the other; “cipher messages of some sort?”

“We think so,” said Carter. “We don’t know yet.”

“I’ve noticed these peculiar advertisements often,” said Jane, studying the clippings, “but I never thought of connecting them with the Hoffs. I wonder—” Fleck and Carter had their heads together and were talking in low tones.

“I wonder,” said the chief, “what young Hoff is up to. He must have known the girl was there to spy on him. I can’t understand his not quizzing her.”

“He’s a cagey bird,” Carter replied. “They are both of them expert at throwing off shadowers. Both of them know, I think, they are being watched.”

“Oh, listen,” interrupted Jane, all excitement. “I believe I can read this cipher. The number of letters in the word in big type at the beginning of the advertisement is the key. See, this word here is ‘remember’—that has eight letters. Read every eighth word in this advertisement. I’ve underlined them.”

Fleck took the paper quickly from her hand and he and Carter bent eagerly over it to see if her theory was correct.

REMEMBER

Please, that our new paste, Dento, will
stop decay of your teeth. Sound teeth
are passports to good health and comfort.
No good business man can risk ill health.
It is closely allied with failure. The
teeth if not watched are quickly gone.

USE DENTO

A genuine, safe, pleasing paste for the
teeth, prepared and sold only by the
Auer Dental Company, New York.

“Stop passports business, closely watched,” repeated Fleck aloud. “That certainly makes sense and fits the facts, too. In the last few days we have drawn the net closely around a gang of supposed Scandinavians who have been busy supplying passports to suspicious-looking travelers. Let’s see the other advertisement.”

Excitedly the three of them read it together as Fleck underscored every fourth word.

DON’T

Forget it is imperative for one and all
to use cleansing agents on teeth that
leave no bad results. “Ship more of
that wonder-working paste immediately.
Workers, employers, wives, all ready to
commend it. Friday’s supply gone,”
writes a druggist, to whom a big shipment
was made last week.

USE DENTO

A genuine, safe, pleasing paste for the
teeth, prepared and sold only by the
Auer Dental Company, New York.

“Imperative all agents leave ship. Wonder-workers ready Friday,” read Fleck. “That’s surely a message, a warning to Germany’s agents to get off some ship or ships before they are destroyed. You, Miss Strong, have heard old Otto talk about the wonder-workers, whatever they are, being nearly ready. I guess he means bombs—bombs to blow up American transports. This message says they will be ready Friday.”

“And to-morrow’s Friday,” said Jane.

CHAPTER XIII THE SEALED PACKET

“Is this Miss Strong?”

Jane, her face blanching, held the receiver in wavering hands for a moment before she could muster courage to answer. She had recognized Frederic Hoff’s voice speaking. What could he want with her now?

“It is Miss Strong,” she managed to answer.

“This is Frederic Hoff. May I come in for a moment? It is most important.”

Again Jane hesitated. Frederic was the last person in the world she felt like seeing just at this moment. Only five minutes before she had arrived home from Chief Fleck’s office. She was under orders to hold herself in readiness to start immediately for the scene of yesterday’s accident. That this trip, unless their plans miscarried, would inevitably result in the exposure and disgrace of both the Hoffs she felt morally certain. To face on friendly terms the man whose downfall she was plotting, the man who only a few hours before had told her that he loved her, seemed a task far beyond her endurance, a situation too tragic for her to cope with.

Duty, her duty to her country, her honor, her patriotism, her affection for her soldier brother, all bade her mask her feelings and seek one more opportunity of leading Hoff to betray himself in conversation if that were possible. Yet, to her own amazement and horror, her heart protested vigorously against such action. Harassed as she was by conflicting emotions, worn out by the trying experiences that had been hers the last few days, she realized at last that she was really in love with Hoff. The throb of joy that she had experienced at the sound of his voice, the thrill that came to her each time she saw him, the delight she found in his presence, the fact that despite all the circumstances, she wanted to be near him, to be with him, convinced her against her will and judgment that her heart was his. In vain she marshalled the damning facts against him. She tried to remember only the expression of murderous hate she had seen on his face the night that her predecessor, the other K-19, had been murdered. She tried to think of him only as a treacherous spy, an enemy of her country forever plotting to destroy Americans, yet she could not. However base and treacherous and low her reason told her Frederic Hoff must be, her refractory heart persisted in beating faster at the prospect of his coming.

Hitherto not much given to self-analysis, she now found herself wondering at herself. What could be the matter with her? Why must she love this rascal? Why could she not fall in love with some decent, clean, patriotic young American, with some man like Thomas Dean? Chauffeur though he was now pretending to be, she knew that he was a college man, well-bred, and traveled. She knew, too, that Dean was in love with her. For him she had a sincere liking, great admiration even, and toward him now she was experiencing that feeling of sympathy a woman always has for the man she cannot love. But her feeling toward Dean, she classified as only that of friendship, nothing at all like the passionate affection that was rapidly drawing her closer and closer to Hoff.

Dared she see him now? Might not her love for him overcome her high desire to be of service to her country? Might she not be led by her unruly heart into betraying to him the fact that he was in the most imminent peril?

Yet she must see him, she told herself. Perhaps this very day he might be arrested and imprisoned. She might never again have the opportunity of seeing him alone and of talking with him. Into her troubled brain came a daring thought. Perhaps it was not too late, even yet, to turn him from his evil course. Was there, she wishfully wondered, any possibility of her leading him, through his love for her, to forsake his comrades, even to betray them? No, she admitted to herself, that was a preposterous idea. He was too dominating, too forceful, too determined, to be influenced to anything against his will.

“May I come in, please?” he kept insisting over the ’phone.

“Only for a minute,” she answered tremulously. “I’m going out soon. I have an engagement.”

“I’ll come right over. I will not keep you long.”

As she awaited his arrival, subconsciously desirous of looking her best in his presence, she stopped almost mechanically before her mirror to adjust her hair, letting him wait for her for a few minutes.

He sprang forward to meet her as she entered the room where he was, his face beaming with delight at the sight of her.

“Jane,” he cried, with a volume of meaning in the monosyllable, as seizing her hand, he held it tightly and gazed earnestly into her face.

Bravely she tried to meet his gaze, to read in his face if she could the object of his unexpected visit, but her eyes fell before his, and the hot blood surged into her cheeks. Within her raged a desperate battle between her head and heart. Mingled with her unwelcome quickening of the pulse at his approach and admiration for his audacity in coming to her when he must know that she knew what he was, there was also an overwhelming sense of futile rage that he, a scheming German plotter, dared intrude his presence into an American home.

“I’m glad to see you appear no worse for your accident,” he said, releasing her hand at last. “You got home all right, without attracting any one’s notice?”

“Oh, yes,” she answered, trying to make her reply seem wholly indifferent and disinterested.

“Your chauffeur is all right, too,” he went on. “I telephoned this morning. He had already left the doctor’s. There’s nothing more the matter with him than a broken arm and a scalp wound. That’s fortunate, isn’t it?”

“Very fortunate,” she admitted.

All at once as they stood there there seemed to have arisen between them an invisible, impenetrable barrier. They faced each other wordlessly, each embarrassed by the knowledge of the secret gulf that was between them. Hoff was the first to recover from it.

“Come,” he said, “sit down. There is something I wish to say to you,—something of the utmost importance, Jane.”

Still struggling with her emotions, Jane allowed him to place a chair for her and seated herself, striving all the while to crush back into her heart the warmth of feeling toward him that always overwhelmed her in his presence, endeavoring to present to him a mask of cold indifference. Yet her curiosity, as well as her affections, had been greatly stirred by his remark. What was it that he was about to say to her? Did he intend, in spite of the insurmountable obstacles between them, dared he, ask her to marry him? Tremblingly she waited for what he had to say.

“Jane,” he said, “you know that I love you. I am confident, too, that you love me.”

“I don’t love you,” she forced her unwilling lips to say. “I can’t. When our country is at war, when she needs men, brave men, how could any true American girl love any man who stayed at home, who idled about the hotels, who—”

“Girl,” his voice grew suddenly stern and commanding, softening a little as he repeated her name, “Jane, dear, let me finish. I love you. There are grave reasons—all-important reasons—why I may not now ask you to be my wife.”

She could not bring herself to tell him, the man she loved, the thing she knew he was.

“I never could be your wife,” she cried desperately, “the wife of a—”

The word died in her throat. She could not bring herself to tell him, the man she loved, the thing she knew he was.

“My Jane,” he said, wholly unheeding her impassioned protest, “you know little yet of what life means in this great world of ours. You, here in your parents’ home, sheltered, protected, inexperienced, have not the knowledge nor the means of judging me. You must take me on faith, on the faith of your love for me. For a woman, life holds but two great treasures, two loves—her husband’s and her children’s. With a man it is different. Love is his, too, but there is something more, something bigger—duty. Here in your country—”

Even in her distress she caught his phrase “here in your country” and turned ghastly white. Always before in talking with her he had spoken of himself as an American. Did he realize, she wondered, that he had at last betrayed himself to her? Was he about to strip the mask from himself and his activities at last, and in the face of it all expect her, Jane Strong, to admit that she loved him?

“Here in your country,” he went on placidly, “women forced by economic conditions have been driven from home into business, into politics, into office-holding, even into war activities. Longing for the clinging arms of little children they are striving to forget in assuming some part in the affairs that belong properly to men. But to the true woman love must ever mean more than duty, more than country. Those are words for men. A woman, if she would find happiness, must follow her heart, must forsake all for the man she loves. A woman’s duty is only to the man she loves, just as a man’s duty is to be true to himself, to his country.”

“But,” she cried, “you told me you were American, that you were born here?”

“Jane,” he persisted, with an impatient gesture, “we will not discuss that now. I love you. You must trust me in spite of everything. I know you will. You must. I can answer no questions. I can make no explanations. I can only say I love you. That must suffice.”

“No, no,” she protested, almost sobbing.

“I came here to-day,” he went on calmly, “to ask a favor of you.”

“A favor,” she cried.

Calming herself she forced herself to look into his face. There was something so monstrously unbelievable about his audacity that she could hardly believe her ears. What sort of a credulous stupid creature was he, she angrily asked herself, that in one breath he could all but confess to her that he was a spy and in the next beseech her to do him a favor. Yet there came to her now a remembrance of her duty to her country. She felt that she must mask her feelings toward him, that if she was to be of service she must endeavor bravely to lead him on. She must try to induce him to confide in her. Hard as her task might be, what was it compared to the work her brother and those other brave American boys had undertaken facing the fire of death-dealing guns, facing the terrible gas attacks, living for days and weeks in those terrible trenches? Reinforced by a sense of duty, she made a pitiable effort at cordiality as she asked:

“What is it you wish of me?”

From one of his pockets he had brought forth a small packet which he held out to her. In spite of her agitation she forced herself to study it observingly, making note that it was tied with strong cord and sealed in several places with red wax. Curiously, too, she noted that on it was written her own name.

“Jane,” said Hoff, “to-night I am going away. I may be absent for only a day or two if all goes well, but it is possible I may never come back,—may never be able to see you again.”

She caught her breath sharply. There was the solemnity of finality in his tones. Where was he going? What might happen to him? She realized that the journey he was about to make was in connection with the plot that she and Chief Fleck were seeking to uncover. Evidently he anticipated peril in what he was about to undertake. Suppose he should be trapped in the commission of some act inimical to America’s welfare? What would happen to him? He would be arrested, of course. More than likely he would be sent to prison. He might even be shot as a spy. What if she were the one responsible for his meeting a disgraceful death? How could she go on with it? She must warn him. She must try to persuade him to give up his plans. She tried hard to steady herself, to think calmly. She must listen to every word he was saying and try to remember it.

“This little packet is for you,” he went on. “I want you to keep it safely. In case anything happens, in the event that within one month I have not returned and you have heard nothing of me, I wish you to open it and keep what it contains. Promise me that you will do what I ask.”

In a panic of indecision she got up from her chair, trying to frame a score of questions, but none of them succeeded in passing the barrier of her trembling lips.

“Promise me,” he said softly yet impellingly, as he placed the little packet in her hand and closed her fingers over it.

“I promise,” she whispered, hardly knowing what she said.

Quickly he caught her in his powerful arms. For just a second he held her there, his face close to hers, his blue eyes burning into hers with a steady inscrutable gaze as if he was trying to read in them the love her lips had refused to speak.

Then, so quickly that it was all over before she quite realized what had happened, he had kissed her passionately full on the lips and was gone.

Overcome with the lassitude which follows emotional crises, trembling in every limb, weak as from a long illness, the girl sank back into a chair, still clutching in her hand the sealed packet Hoff had entrusted to her. Minute after minute she sat there with staring eyes, with heart beating madly, with her whole body racked with the torment of her thoughts.

Slowly she lifted the packet and turned it over and over, wondering what it could possibly contain, questioning herself as to what could have been Frederic Hoff’s motive in entrusting it to her. Was there, she wondered, under those seals, some evidence of his guilt and treachery that he had not dared to leave behind him? He must have known that she suspected him and was seeking to entrap him. Had he, knowing all this, but sensing the love for him that he had kindled in her, taken advantage of it and extorted from her her promise to keep it safe?

Wherein lay her duty now? More than ever she was certain that Frederic Hoff was on some hazardous mission for the enemy. He had all but admitted his nationality to her. Her own country’s welfare demanded that the Hoffs’ plans should be discovered and thwarted. Should she, or should she not open the package? Possibly it contained some secret code, some clue to the dastardly activities in which he and his uncle were engaged.

But her heart rebelled. She recalled what he had said, that she must take him on trust. The memory of his burning kiss, of that last earnest look he had given her, refused to be forgotten. Whatever he was, however base the work in which he was engaged, she knew down deep in her heart that Frederic Hoff had been earnestly sincere when he had said that he loved her.

As she debated with herself what she ought to do, the telephone rang again. It was Chief Fleck.

“Can you meet me at the 110th Street subway station in half an hour?” he asked. “I’ll be waiting in my car. Arrange it, if you can without arousing your family’s suspicion, to be away all night.”

“I will be there,” she answered.

As she turned away from the telephone with sudden resolve she thrust the sealed packet, still unopened, into the bosom of her gown.

“I promised him,” she said almost fiercely. “I’ll keep my promise. That much at least I owe our love.”

CHAPTER XIV THE MOUNTAIN’S SECRET

In a turmoil of mental anxiety Jane waited the arrival of Chief Fleck at the place he had designated. She was still badly wrought up by the scene through which she had just passed with Frederic. There were moments when her heart insisted that, regardless of the despicable crimes that were laid at his door, she should forsake everything for him, for the man she loved. Had there been in her mind the slightest possible doubt as to his guilt she might indeed have wavered, but the evidence of his treachery seemed too manifest! She loathed herself for caring for him and felt it her sacred duty to go on with her work of aiding the government in trying to entrap both of them; yet how could she ever do it?

As she waited she debated with herself whether or not to tell Chief Fleck what had passed between herself and Frederic. After all, why should she? That was her own secret, not the country’s. If she stifled her love, and gave her best efforts to aiding the other operatives in running down the conspirators, what more could be expected of her? Certainly she was not going to tell any one of the sealed packet Frederic had entrusted to her. She had promised him she would keep it safe. Surely there could be no harm in that, yet the little parcel, still in the bosom of her gown where she had thrust it, seemed to be burning her flesh and searing itself into her very soul.

In strong contrast with her own spirit of martyrdom was Fleck’s manner. Never before had she seen him in such high spirits as he was when he drew up before the subway station in a low car built for speed. On the seat beside the chauffeur was a young man whom she recognized as another of the operatives. As Fleck swung the door of the tonneau open for her she noticed lying on the floor under a rug several rifles and drew back questioningly.

“Come on, Miss Strong,” he cried gaily. “Don’t be afraid of them. We may be glad we have them before we return from our hunting expedition.”

“But,” she asked hesitatingly as she took her seat beside him, “you don’t expect to shoot these men—without a trial.”

Her heart seemed torn in anguish as she sensed anew the peril that lay ahead for Frederic. Misgivings that she might be unable to fulfil her task seized her, and she was smitten with reproach for her own conduct toward him. Why, an hour ago, when there was still opportunity, had she not warned Frederic? If he were really sincere in the affection he professed for her maybe she might have persuaded him, if not to betray his comrades, at least to abandon them and escape from the country. Yet even now her reason told her that any plea she might have made would have been worse than futile. Above and beyond his love for her she understood that he held sacred what he conceived to be his duty, his misguided duty to his erring country. It was too late now for regrets, for repentance, too late for her to do anything but to try to serve her country, cost her what it might, yet anxiously she awaited Chief Fleck’s reply to her question.

“Wouldn’t I shoot them all on sight, gladly, the damned spies,” he responded. “That’s the great trouble with this country, Miss Strong. We’re too soft-hearted and chivalrous. The Germans realize that war and sentiment have no place together. If killing babies and destroying churches will in their opinion help them win the war they do it without compunction. The civilized world decided that poison gas was too brutal and dastardly for use, even against an enemy, but that didn’t stop the Huns from using it. They put duty to Germany above all else, and if their country expects it are ready to rob, murder, use bombs, betray friends, do anything and everything, comforted by the knowledge that even if we do catch them at it here in this country all we will do to them will be put them in jail for a year or two. If I had my way I’d shoot them all on sight.”

“Without any evidence—without trying them?” questioned Jane.

“Without trial, yes—without evidence, no; but in the case of these Hoffs we have evidence enough to stand them both up and shoot them.”

“Have you learned more?” she asked quickly. “Is Frederic, too, involved with his uncle?”

He shot an appraising glance at her. He had been inclined to regard Dean’s suspicion that she was in love with the younger Hoff as the mere figment of jealousy, but where two young persons of the opposite sex are thrown together, there is always the possibility of romance. Jane colored a little under his searching glance, yet what he read in her face seemed to satisfy his doubts, and he made up his mind to take her fully into his confidence.

“Thanks to your quick wit in reading those advertisements,” he said, “we have now a fairly complete index of the Hoffs’ activities in the last six months. I have been spending the last two hours in going over all the Dento advertisements that have appeared. For weeks they have been sending out a regular series of bulletins.”

“Bulletins about what?” asked Jane.

“About everything of interest to the secret enemies of our country: explanations of where and how to get false passports, detailed statements of the sailings of our transports, directions for obtaining materials for making bombs, instructions for blowing up munition plants, suggestions for smuggling rubber, orders for fomenting strikes. They even had the nerve to use the name of William Foxley, signed to a testimonial for Dento.”

“Who is William Foxley?” asked Jane curiously.

“In the Wilhelmstrasse code that was in use when Von Bernstorff was still in this country; in sending their wireless messages they made frequent use of proper names which had a code meaning. Boy-ed was ‘Richard Houston,’ Von Papen was ‘Thomas Hoggson’ and Bolo Pascha was always mentioned as ‘St. Regis,’ In this same code ‘William Foxley’ always meant the German Foreign Office.”

“But surely you did not learn this from the advertisements?”

“Not at all. Hugo Schmidt, who was reputed to be the paymaster of the gang, was caught trying to burn a copy of this code at the German Club. With the records of their wireless messages our government managed to reconstruct the whole code. The use of a word or two from this code in these advertisements is most significant. It shows that whoever prepared these advertisements was high in the confidence of the German government. Only the very topnotch spies are likely to be permitted to know the diplomatic code.”

“And you think, then, that Otto Hoff may be the head of the conspirators in this country?” said Jane.

“Not Otto—Frederic,” said Fleck quickly. “The young man, I am certain, was the director, probably sent out from Berlin after the country became too hot for Von Papen and Boy-ed. The old man, I believe, merely carried out his orders. I doubt even if they are uncle and nephew.”

“I think you are wrong about that,” protested Jane. “Whenever I was listening over the dictograph it was always the old man who was so bitter against America. It was he who talked about the wonder-workers and the necessity for haste. I never heard Frederic say anything—anything disloyal, that is.”

“The fact that he knew enough to keep his mouth closed shows that he is the more intelligent of the two. Don’t forget, too, that at times he even dared to don the uniform of a British officer. You saw him yourself. Undoubtedly he is the more dangerous of the pair.”

“But who read these advertisements?” asked Jane, seeking to change the subject. “For whom were the bulletins intended?”

“It was one of their ways of keeping in communication with their thousands of secret agents all over this country. I wouldn’t be surprised if occasionally these advertisements were printed in Texas papers and shipped over the border into Mexico. We have been watching the mails and the telephone and telegraph lines for months, yet all the while Mexico has been sending messages across, telling the U-boats everything they needed to know. We never thought of checking up the advertising in papers in the Mexican mail.”

“But what about the messages old Mr. Hoff left in the bookstores? Was that part of the plan, too?”

“It may have been simply a duplicate method of communication in case the other failed. The Germans here know that they are constantly watched and take every precaution. We’ll land that girl as soon as we have the Hoffs safe behind the bars, and then we’ll soon see if Carter’s dachshund theory was right.”

“But who,” asked Jane, “is the spy in our navy? Who signalled the Hoffs’ apartment and supplied them with the news about our transports? Was it Lieutenant Kramer?”

“Probably,” said Chief Fleck carelessly, “that is not my end of the work. It is up to the Naval Intelligence Bureau to clean out the spies in the navy. I’m after the boss-spy. After we land him it will be easier to get the small fry. A defiant German prisoner once boasted to me that Germany had a man on every American ship, in every American regiment, and in every department in Washington. I suspect it comes pretty near being true. A country that has so many citizens with German names and such an enormous population of German descent has its hands full.”

As they talked the chief’s car had crossed the ferry, and turning north through Englewood, was heading rapidly in the direction of West Point.

“Where are we going now?” Jane ventured to ask. “To the place where I was yesterday—where we had the accident?”

“Not directly,” the chief replied. “I sent Carter and some men up there ahead of us to do some reconnoitering. I’ll get in touch with Carter at the restaurant at the State Park. He was to call me up. We are nearly there now.”

As the car swung into the park and stopped before the entrance of the two-story restaurant building, Fleck sprang hastily out and started for the telephone but stopped abruptly at the sight of a young man with bandaged head and with one arm in a sling who rose from the concrete steps of the building to greet him.

“Why, Dean,” he exclaimed in amazement, “what are you doing here? How did you get here?”

“You don’t think I was going to be left out at the finish,” laughed the chauffeur.

“But your injuries, your arm—”

“Both all right, as right as they’ll be for several weeks.”

“But how did you know we were coming here? How did you manage to get here?”

“Carter stopped on his way out to make sure about the road. I wanted to come with him, but there was no room in his car. He refused to bring me, anyhow. I managed to worm out of him what your plans were, and the doctor’s jitney did the rest.”

“Well,” growled the chief, with simulated indignation, though secretly delighted with Dean’s show of spirit, “I suppose there’s nothing else to do but to take you along. Climb in there beside Miss Strong.”

As Dean approached the car Jane rose in amazement.

“Oh, Thomas, Mr. Dean,” she cried, “I’m so glad to see you. I was afraid yesterday that you had been badly hurt.”

“It was a close shave for both of us,” he admitted, flushing with delight at the warmth of her greeting, “but what are you doing here? The Chief had no business to bring you on a trip like this.”

All his affection for the girl had revived at this unexpected sight of her, and with a lover’s righteous anxiety he resented Fleck’s having exposed her to the probable perils of this expedition to the enemy’s secret lair.

“They needed me,” she said simply, “to show them the way.”

“That need exists no longer,” he protested, “since I am here. The Chief must send you back.”

“Don’t be absurd,” she objected warmly.

“But it is no place for a woman,” he insisted doggedly, kicking meaningly at the rifles on the floor of the car. “There may be a fight. These men are desperate and dangerous and more than likely will resist any attempt to arrest them.”

“I want to be there to see it if they do,” said Jane calmly.

“Please, won’t you, for my sake,” he begged, “go back home or at least wait here for us?”

“I won’t,” said the girl doggedly.

“I’ll ask the Chief to send you back.”

“Don’t you dare,” she retorted hotly, resenting his air of protection toward her.

She was glad for the presence of the two other men in the car. She sensed that it was only their being there that kept Dean from making a scene. There was nothing in his manner toward her now of the obsequious chauffeur. While she admitted to herself that there was no longer the necessity for his continuing in his fictitious character she strongly resented his loverlike jealousy for her welfare and welcomed the chief’s return, for she saw from his face, as he came running up to the car, that he had received some sort of news that had highly delighted him.

Almost before he was in the car he had given orders to start, leaving no opportunity for Dean to make his threatened protest against Jane’s presence.

“I got Carter on the ’phone,” Fleck explained hurriedly as they swung out of the park and turned northward. “He has succeeded in locating the place the Hoffs go every week. It is about three miles back off the road, over toward the river from the place where you two had that accident yesterday. Away off there in the woods in a deserted locality is a sort of club, the members of which are Austrians or Germans. They have given it out that they are health enthusiasts and mountain climbers, ‘Friends of the Air,’ they call themselves.”

“Who are they really? What are they doing there?” asked Jane interestedly.

“Carter has not had time yet to learn much about them. The place was some sort of a health resort or sanitarium that failed several years ago. Last summer it seems to have been taken over by this bunch of Germans. At times there are only two or three of them there, but recently the number has increased. Carter thinks there must be a dozen men there now.”

“How did he locate the place?” asked Dean.

“Carter is a real detective,” said the chief enthusiastically. “He reasoned it out that where there were Germans there must be beer. He scouted along the main road until he found a wayside saloon where, as he had shrewdly suspected, they got their liquid supplies. From the proprietor of the place and the hangers-on he had no trouble in getting the information he wanted without arousing their suspicions.”

“Where is Mr. Carter now?” asked Jane.

“He’s waiting for us a few miles up the road.”

“He has only four men with him, hasn’t he?” questioned Dean.

“That’s all.”

“And there are four of us here.”

“Three and a half,” said the chief, motioning to Dean’s bandaged arm.

“It’s my left arm,” he retorted. “I can handle a revolver, at least, with my good arm.”

“And I can shoot, too,” boasted Jane; “that makes nine of us.”

“Nine of us against twelve of the enemy,” said the chief thoughtfully. “It looks like a busy evening.”

“And don’t forget,” warned Jane, “that the Hoffs are coming up this evening. At least young Mr. Hoff told me this morning that he was going away this evening. That makes two more on the other side.”

“And one of them,” muttered Fleck, “a mighty dangerous man.”

CHAPTER XV THE HOUSE IN THE WOODS

At last they had reached their goal, the place which the two spy suspects undoubtedly had been in the habit of visiting regularly every week for months past.

Sheltered by a great rock and the underbrush about it, Jane, with Fleck and Thomas Dean, peered eagerly out at a dingy, weather-beaten frame structure which neighborhood gossip had told them was the sheltering place of the “Friends of the Air.” In its outward appearance at least, Jane decided, it was disappointingly unmysterious. It looked to her merely like a cheap summer boarding-house that had gone long untenanted. There was a two-story main building, cheaply constructed and almost without ornament, sadly crying for new paint, and the usual outbuildings found about such places in the more remote country districts.

Still from Chief Fleck’s manner she was certain that he regarded their achievement in locating the place as of the highest importance. They had run their two automobiles noiselessly up the lane leading from the main road until they were perhaps half a mile distant from the house and then had concealed them in the woods near-by, being careful to obliterate all traces of the wheel tracks where they had left the lane. Making a détour among the trees they had reached their present position not more than three hundred yards away from the buildings. They had carried the rifles with them, and these now were close at hand, hidden under the log on which the three of them were sitting. Carter, with the other men, under Fleck’s orders, had divided themselves into scouting parties and had crept away through the woods to study their surroundings at still closer range while the waning afternoon light permitted.

At first glance one might have been inclined to believe the buildings untenanted. There seemed to be no one stirring about the place, and some of the unshuttered windows on the second floor were broken. The only indications of recent occupation were a pile of kegs at the rear of the house and near-by a heap of freshly opened tin cans. Near one of the larger outbuildings, too, was a pile of chips and sawdust.

“There does not seem to be any one about,” whispered Jane. “What do you suppose they do here?”

“I can’t imagine yet,” said Fleck with an impatient shake of his head. “The fact that this house is important enough for the Hoffs to visit once a week makes it important for us to cautiously and carefully investigate everything about it. It may be a secret wireless plant away off here in the woods where no one would think of looking for it. It might be a bomb factory where their chemists manufacture the bombs and explosives with which they are constantly trying to wreck our munition plants and communication lines. Perhaps it is just a rendezvous where their various agents, the important ones engaged in their damnable work of destruction, come secretly to get their orders from the Hoffs and to receive payment for their hellishness accomplished.”

“It’s all so funny, so perfectly absurd,” said Jane with a nervous little laugh.

“Absurd,” cried Fleck indignantly, “what do you mean? It’s frightfully serious.”

“Of course, I understand,” Jane hastened to say. “I was just thinking, though, how funny we are here in America, especially in the big cities. We know nothing whatever about our neighbors, about the people right next door to us. In one apartment we’ll be doing all we can to help win the war, and in the apartment next door the people will be plotting and scheming to help Germany win, and it is only by accident we find out about it. Take my own father and mother. They haven’t the slightest suspicion of the people next door. They would hardly believe me if I told them the Hoffs were German spies. They see them every day in the elevator. Young Mr. Hoff has been in our apartment several times. My mother has met him and talked with him. I was just thinking how amazed and horrified she will be when she hears about it and learns what I have been doing.”

“You are perfectly right,” said Fleck soberly. “We are entirely too careless here in America about our acquaintances and neighbors. We know that we are decent and respectable, and we’re apt to take it for granted that everybody else is. We don’t mind our neighbors’ business enough. Nobody in a New York apartment house ever bothers to know who his neighbors are or what their business is, so long as they present a respectable appearance. I know New York people who live on the same floor with two ex-convicts and have lived there for three years without suspecting it. We should have here in America some system of registration as they have in Germany. Tenants and travelers ought to be required to file reports with the police, giving their occupation and other details. If that plan were in use here enemy spies would lack most of the opportunities we have been giving them.”

“Yes,” said Dean, “you are right. I’ve lived in Germany. Over there a crook of any sort can hardly move without the police knowing it. Their system certainly has its good points.”

“It surely has,” Fleck agreed. “If the Prussians’ character were only equal to their intelligence they would be the most wonderful people in the world, but they are rotten clear through. They have no conception of honor as we understand it. Only the other day I read of a Prussian officer who led his men in an attack on a chateau, guiding them by plans of the place he had made himself while being entertained in the chateau as a guest before the war.”

“Don’t you think any of them have a sense of honor?” asked Jane in a troubled tone.

Her mind had reverted, as she found it frequently doing, to Frederic Hoff and the sealed packet he had entrusted to her. He had professed to love her and had demanded that she trust him. Was it, she wondered, all a base pretense on his part? Was he—for Germany’s sake—taking advantage of her affection for him to make her the unwitting custodian of some secret too perilous for him to carry about with him? Perhaps that little parcel she was carrying in the bosom of her gown contained the code he and his uncle used? Had it not been for Dean’s presence she might have been tempted to take Fleck into her confidence and tell him of the peculiar incident, though in spite of all she knew about him she felt that Frederic Hoff’s feeling for her was real, and that toward her he always would show only respect and honor, as he always had done hitherto; and yet—

Before the chief had time to answer her question Dean with a whispered “hist” pointed to a path in the rear of the buildings they were watching. Behind the house two rugged hills, their sides of precipitous rock so steep that they hardly afforded a foothold, came down close together, making a V-shaped cleft through which a narrow path ran in the direction of the river. Looking toward this cleft to which Dean was pointing they now saw a group of workmen approaching the house.

All of them were in the garb of mechanics, yet as they approached in single file down the path, the quick eye of the chief noted that they were keeping step.

“They’ve all of them seen service,” he muttered to himself, “either in prison or in the German army.”

Some of them carried kits of tools, and they walked with the air of fatigue that results from a day of hard physical work. They seemed to have no suspicion as yet that they were under observation, for as they walked they chatted among themselves, the sound of their German gutturals reaching the watchers, but unfortunately not distinctly enough to be audible. Dean was busy counting them.

“There are fourteen,” he announced, “two more than we were expecting to find here.”

“At what do you suppose they are working?” asked Jane curiously.

“Here comes Carter,” replied Fleck. “Perhaps he can tell us. His face shows that he has learned something.”

Carter, crawling rapidly but silently through the underbrush, approached breathlessly, his sweaty, begrimed countenance ablaze with excitement.

“What’s up?” asked Fleck, as soon as he was within hearing.

“My God, Chief,” he gasped, “they’ve got three big aeroplanes out there on a plateau overlooking the river—three of them all keyed up and ready to start.”

“Friends of the Air,” muttered Fleck; “so that’s what it means.”

“They’ve evidently smuggled all the material up and built the three planes right here,” Carter went on. “I watched them putting on the finishing touches and testing the guy-wires. There is a machine shop, too, rigged up in one of those outbuildings. The thing that gets me is how they got the engines here. All the planes are equipped with powerful new engines.”

“If there are traitors in the army and navy, why not in the aeroplane factories, too?” suggested Fleck. “A spy in the shipping department could easily change the label on even a Liberty motor intended for one of Uncle Sam’s flying fields. Even when it didn’t turn up where and when it was expected, it would take government red tape three months to find out what had become of the missing motors.”

“These machines”—said Jane suddenly, “they must be the ‘wonder-workers’ old Mr. Hoff was always talking about.”

“And that last advertisement we read,” Dean reminded them, “announced that the wonder-workers would be ready Friday. It looks as if we got here not a minute too soon.”

“You bet we didn’t,” said Carter. “Every one of those three planes is fairly loaded down with big bombs, scores of them.”

“To bomb New York,” said Fleck soberly; “that’s their plan. Zeppelins for England, big guns to shell Paris, bombs from the air for New York. It’s part of their campaign to spread frightfulness, to terrorize the world. Undoubtedly that is the reason Berlin sent Frederic Hoff over here, to superintend the destruction of the metropolis. There have been whispers for months and months that the city some day was to be bombed, but we never were able to discover their origin.”

“And not a single anti-aircraft gun or anything in the whole city to stop them, is there?” cried Jane. “Wouldn’t it be terrible?”

Fleck smiled grimly.

“Any foolhardy German who tries to bomb New York from the air has a big surprise coming to him—a lot of big surprises. The war department may not have been doing much advertising, but it has not been idle.”

“Then we have some anti-aircraft guns!” cried Jane delightedly. “I never heard anything about them.”

“That would be telling government secrets,” said Fleck, smiling mysteriously, “but I’d just like to see them try it. I have sort of a notion to let them start their bombing.”

“Oh, no, we mustn’t,” Jane insisted. “We mustn’t let those aeroplanes ever start. Can’t we do something right away to cripple them?”

“There’s plenty of time,” the chief assured her. “It is best for us to wait until after dark. The early morning would be ideal time for an aerial attack on the city, when everybody is helpless and asleep. There’s generally a fog over the river and harbor, too, before sunrise at this season of the year, and that might help them to mask their movements. It would take an aeroplane less than an hour to reach the city from here, so that there is no likelihood of their starting until long after midnight. That gives us plenty of time, and besides we must wait until the Hoffs arrive.”

“That will make two more—sixteen of them against our nine,” warned Dean.

“We cannot help it how many of them there are,” said Fleck. “It is of vital importance for us to know just what their plans are. It is unlikely that they will post guards to-night in this secluded spot, where they have been at work in safety for months. As soon as it is dark we can smash the aeroplanes.”

“That will be easy,” said Carter. “I know something about aeroplanes. Cut a couple of wires, and they are out of business. Sills, one of my men, is posted on bombs, and he’ll know just how to fix the fuses to render them useless.”

“What’s more,” said Fleck, “if I understand German thoroughness, they will go over their final plans in detail to make sure that everything is understood. The darkness will let us slip up closer to the house, and we may be able to overhear what they say. Don’t forget, too, that our main job is to catch the Hoffs red-handed.”

“That’s right,” said Dean. “They are the brains of the plot. These other fellows are just workmen taking orders.”

“I’m puzzled,” said Fleck, “to know what they plan to do with the aeroplanes after the bombing has taken place. There is not one chance in a thousand of their being able to return here in safety without discovery. It will be sure death for the aviators that take up those machines.”

“Sure death!”

With a shudder Jane recalled what Frederic had said to her only a few hours ago as they parted—that he was going away and might never return. Was this what he had meant? Was he, Frederic, to be one of the foolhardy three who proposed to forfeit their lives in this desperate attempt to deal destruction from the air on a sleeping city, to wreck innocent homes, to cripple and maim and destroy helpless babies and women? She could not, would not believe it of him. That he had the courage and daring to undertake such a perilous task she did not doubt. She realized, too, that the controlling motive of all his actions was his high sense of duty toward his country, and yet in spite of all that she had learned about the plots in which she was enmeshed, her heart refused to believe that he ever could bring himself to participate in such wanton frightfulness. She recalled the spirit of mercy that he had shown toward herself and Thomas Dean after the accident as contrasted with the brutal indifference of his uncle. She kept hoping against hope that something might happen to prevent his arriving here. Devoutly she wished that she might awake and find that it was all a terrible mistake, a hideous unreality, and that the “Friends of the Air” were not in any way associated with the Hoffs.

Yet her reason told her it must all be true, terribly, infamously true, and that he was one of them, perhaps the leader of them.

One by one the members of the various scouting parties had come creeping in through the forest. All of them verified what Carter had already reported. One man, more venturesome than the others, had even dared to creep close up to the rear of the house and had seen through the window the workmen, gathered about their supper of beer and sausages, toasting the Kaiser with the unanimity of a set formality.

As the light waned, secured from observation by the undergrowth between their position and the house, they sat there discussing plans of action, selecting while the light still permitted the most advantageous posts from which they could make a concerted rush on the plotters. Fleck was insistent that they should do nothing to betray their presence until after the Hoffs had arrived, and Dean once more voiced his protest against Jane taking part in the attack. “I will be of far more use than you with your crippled arm,” she resentfully insisted. “I can handle a revolver as well as any man, and a rifle, too, if necessary.”

“Dean is right,” Fleck decided. “It is no work for a woman. Here is an automatic, Miss Strong. You will stay here until after we have rounded them up. If we get the worst of it, which is not likely to happen, make your way to the automobile and telephone the commandant at West Point.”

Reluctantly Jane assented. She realized that further protest was useless. Fleck was in command, and his orders must be obeyed unquestioningly if their plans for the capture of the plotters were to be successfully carried out.

Presently they heard in the distance the sound of an automobile approaching, and soon they could distinguish its lights as it negotiated the rough, winding woodland road that led to the house. A toot from the horn as it arrived brought the men within the house tumbling out the front door with huzzas of greeting for their leaders, and Fleck observed that all the men as they came out automatically raised their hands in salute.

“Ex-German soldiers, every one of them,” he muttered.

As the Hoffs got out of the car a shaft of light from the opened front door threw the figures of the new arrivals into sharp relief, and Jane saw, with a shudder of terror, that Frederic was dressed in an aviator’s costume. There was no longer any doubt left in her mind that he was one of those going to certain death, and a dry sob choked her.

The Hoffs passed within the house, and the door was closed.

“Now,” cried Fleck, “to your stations, men. Each of you take a rifle. You stay here, Miss Strong. Come on, Carter.”

CHAPTER XVI THE ATTACK ON THE HOUSE

In accordance with instructions already issued two of Fleck’s men rushed for the front of the house, where with rifles ready they stood guard, while the others took cover in the shadow of one of the outbuildings a few feet distant from the rear entrance.

Apparently the plotters had been so long undisturbed in their mountain fastness that they had ceased to take even the most ordinary precautions against surprise. So far as could be discovered they had posted no guards over the aeroplanes and their deadly cargo, nor at either of the two doors to the main building. Nevertheless Fleck, as he crept stealthily up to the building with Carter at his side, took out his automatic and held it in readiness, and Carter followed his example.

There was no moon to reveal their movements as they approached the rear of the house. The evening was warm, and one of the windows had been left open. Noiselessly they crept up to it and looked within. It opened into a large room used as a dining hall, where they could see all of the men clustered about one of the tables, at the head of which sat old Otto Hoff with Frederic at his side. On the table before him was what appeared to be a rough map or blueprint. Frederic and five of the other men, Fleck observed, now wore aviation costumes.

“Comrades,” old Otto was saying in German, “here is the course. You will have no difficulty in following it. Down the river straight till you see the lights of New York. You each understand what you are then to do, yes?”

“Certainly,” three of the men, the pilots evidently, responded.

“Let us, to make sure,” old Otto insisted, “once more rehearse it. Much there is at stake for the Fatherland. You, Anton and Fritz, will blow up the transports and the warships that guard them. Six great transports are lying there, ready to sail at daylight The troops went aboard to-night. We waited until it was signalled that it was so. You must not fail. The biggest of those transports once belonged to Germany. You must teach these boastful Americans their lesson. That one boat you must destroy for certain. Beside the transports to-night lie five vessels of war, two battleships, three cruisers. Them you must destroy also, if there is time. To each transport, two bombs, to each warship, two bombs—twenty you carry. If all goes well, two you will have left. With these do what you will, a house, a church, it matters not—anything to spread the terror of Germany in the hearts of these money-grabbing Americans.”

“It will be done,” said Anton solemnly.

“I have thrown bombs before. You can trust me,” said Fritz.

“You, Hans and Albert,” old Otto went on, “will fly over the city at good height. When you reach the end of the island you turn to the left, so, and come down close that your aim may not miss. Here will be the Brooklyn Navy Yard,”—he indicated a place on the map. “If there is fog the bridges will locate it for you. Smash the ship lying there, the shops, the dry docks; if it is possible blow up the munitions stored there.”

“I know the place well,” Hans replied. “I worked there many months. I can find my way in the dark. It will be done.”

“And to you, Herr Captain,” said Otto, turning to Frederic and saluting, “to you, whom the War Office itself sent here to oversee this all-wonderful plan of mine which it has seen fit to approve, to you and your mate falls the greatest honor and glory. You—”

A suppressed sob at his side caused Fleck to turn quickly and lay his finger on the trigger of his revolver. There, close beside him, listening to all that had been said, was Jane. Left alone in the darkness she had found it impossible to obey the chief’s orders and remain where she was. Every little sound about her had carried new terrors to her heart. Hitherto she had not felt afraid, but the solitude filled her mind with wild imaginings. She was seized, too, by an irresistible desire to know what part Frederic was playing in this drama of the dark. Was his life in peril? Were Fleck and Carter now gathering evidence that would bring about his conviction, perhaps his shameful death? She must know what was happening. Quietly she had stolen up to peer through the window.

Fleck, as he recognized her, with an angry gesture of warning to be silent, turned back to hear what Otto was saying.

“—you, Frederic, have the glory of leading the expedition, of bombing that damned Wall Street which alone has kept Germany from winning her well-deserved victory. You will destroy their foolish skyscrapers, their banks, their business buildings. Your work will end this way. You will strike terror into the cowardly hearts of these American bankers whose greed for money has led them to interfere with our great nation’s rightful ambition. You shall show them that their ocean is no protection, that the iron hand of our Kaiser is far-reaching. Do your work well, and they will be on their knees begging us for peace.”

“God helping me,” said Frederic, “I will not fail in my duty to my country.”

There was something magnificent in his manner as he spoke, something almost regal, and Fleck regarded him with a puzzled air. Who was he, this man who had been sent out from Germany on this mission—this man to whom even old Otto paid deference? Despite the assurance with which he had spoken Fleck had observed in Frederic an uneasiness, a watchfulness, that none of the others seemed to exhibit. He had the appearance of alertly listening, listening, for what? Fleck’s first thought was that he might have overheard the little cry that Jane had inadvertently given, but he quickly dismissed this theory. If Frederic had heard that sound it would have alarmed him, and the look in his eyes now was one of expectancy rather than of fear.

Jane, too, was puzzled and distressed. With trembling hands she clutched at the sill of the window for support as she heard Frederic assent to old Otto’s plans for him. Her estimate of his character made it seem incredible that he would willingly lend himself to this work of wholesale murder, yet she could no longer doubt the evidence of her own ears. With overwhelming force it came to her that this man who so readily agreed to such bloody, dastardly work as this, must undoubtedly be also the murderer of that K-19 whose body had been found just around the corner from her home. Bitterly she reproached herself that she had allowed herself to care for him. Shamedly she confessed to herself that she still loved him—even now.

“Your great work accomplished,” Otto continued, “remember your orders. Forty miles due east of Sandy Hook there will be lying two great submarines, waiting to take you off—not U-boats, but two of our powerful, wonderful new X-boats, big enough to destroy any of their little cruisers that are patrolling the coast, fast enough to escape any of their torpedo boats. How important the war office judges your work you may realize from this—it is the first mission on which these new X-boats have been dispatched. They are out there now. We have had a wireless from them. They are waiting to convey six heroes back to the Fatherland, where the highest honors will be bestowed on them at the hands of our Emperor himself. Herr Captain and Comrades—”

He stopped abruptly, and there came into his face a pained look of surprise, of terror.

“Was is dass?” he cried in alarm.

One of Fleck’s men in hiding out there in the shadow of the building had been seized by an irresistible desire to sneeze.

The terrifying suspicion that there had been some uninvited spectator outside, listening to their plotting, swept over the whole room. The whole company, hearing the sound that had alarmed old Hoff, arose as one man and stood tensed, stupefied with fear, gazing white-faced in the direction from which the sound had come.

Fleck, rudely brushing Jane aside, dropped back from the window and blew a sharp blast with a whistle. At the sound his men came running up with their rifles ready.

Inside, the man called Hans, seizing an electric torch, dashed to the door, and pulling it wide, rushed forth, his torch lighting the way before him. Before he even had time to see the men gathering there and cry an alarm, a blow from the butt of Carter’s revolver stretched him senseless on the stoop.

“In the name of the United States I command you to surrender,” cried Fleck, springing boldly into the open doorway, revolver in hand; “the house is surrounded.”

Instantly all within the room was confusion. Some of those nearest the door, seeing behind Fleck the protruding muzzles of the guns, promptly threw up their hands in token of surrender. Others bolted madly for the front door, only to find their egress there blocked by the rifles in the hands of the guard that Fleck had had the foresight to station there.

Old Otto, the pallor of fear on his face giving away to an expression of demoniac rage, drew a revolver and aimed it straight at Fleck. Jane, who unbidden had followed the raiders as they entered and now was standing wide-eyed in the doorway watching the spectacle, was the only one to see that just as old Otto pulled the trigger his nephew, whether by accident or design, she could not tell, jostled his arm, sending the bullet wide of its mark.

“Come on, men,” cried Fleck, advancing boldly into the room.

Eight of the Germans, piteously bleating “Kamerad” stood against the wall near the door, their hands stretched high above their heads.

“Guard these men, Dean,” cried Fleck, as with Carter close at his side he dashed into the fray.

One man already lay senseless outside, eight had surrendered. Four had fled to the front of the house. That left only the two Hoffs and one other man against five of them. It was Fleck’s intention to try to overpower the trio before the four who had fled returned to aid them. Jane, amazed at her own coolness, stood beside Dean, her revolver out, helping him guard the prisoners.

Frederic all the while had been standing by his uncle’s side, strangely enough appearing to take little interest or part in the battle. Old Otto, though, despite his years, was fighting with vigor enough to require both the work of Fleck and Carter to subdue him. Vainly he struggled to wrench himself free from their grasp and use his revolver again. Fleck’s strength pulling loose his fingers from the weapon was too much for him. As he felt himself being disarmed, in a frenzy he tore himself loose from both of them and seizing a chair, swung it with all his strength against the hanging lamp above the table that supplied the only light in the room.

In an instant the room was in darkness. The four from the front, rushing back to aid their comrades in answer to old Otto’s cries, found themselves unable to distinguish friend from foe. Fleck’s men dared not use their weapons in the darkness. Back and forth through the room the opposing forces struggled, the air thick with cries and muttered oaths, the sound of blows making strange medley with the rapid shuffling of feet.

Jane, remembering the electric torch that had been carried by the man Carter had struck down, felt her way to the door and retrieved it from his senseless fingers. Returning, she flashed it about the room, endeavoring to assist Fleck by its light. As she let the beam fall on Frederic she heard a muttered curse at her side and turned to see Thomas Dean aiming his revolver directly at the younger Hoff. With a quick movement she thrust up his arm, and the bullet buried itself in the wall above his head.

“What are you trying to do,” snapped Dean; “help that damned spy to escape?”

“He wasn’t trying to escape,” she angrily retorted. “Look—quick—mind your prisoners.”

He turned just in time to see the Germans behind him lowering their arms. In another second they would have been on his back. At the sight of his brandished revolver, their arms were quickly raised again.

Meanwhile Fleck’s men, guided by Jane’s light, were laying about them with their rifles clubbed. The plotters were at a disadvantage in not realizing how few there were in the attacking party. Fleck’s announcement that the house was surrounded had both deceived and disheartened them. When three of their number had been knocked senseless to the floor the others surrendered and joined the group that stood with hands up.

To Fleck’s amazement it was Frederic Hoff who led in the surrender.

“Watch that young Hoff,” he whispered to Carter. “I can’t understand his giving up so easily. It may be only a ruse on his part.”

“Perhaps he’s afraid the girl will be hurt,” whispered Carter, but Fleck was not there to hear him, having dashed forward to where old Otto was still fighting desperately.

Somehow in the melee the old man had again got hold of a revolver, and just as Fleck seized him he fired again. The bullet, aimed at Fleck, left him unharmed, but found a mark in Thomas Dean, who with a little gurgling cry, fell forward at Jane’s feet. Carter turned at once to guard the prisoners, as Fleck, with a cry of rage, felled old Hoff to the floor, harmless for the present at least.

Sending one of his men to the other rooms in search of lamps Fleck soon had all the prisoners safely shackled, both hand and foot, none of them offering any resistance. Investigation showed that old Hoff in falling had struck his head in such a way that his neck was broken, killing him instantly. The three who had been clubbed were not seriously injured, and as soon as they revived were shackled as the others had been.

Jane, seeing Dean collapse, had turned to aid him and for some time had been bending over him, trying to revive him. He had opened his eyes, looked up into her face and had tried to say something, and then had collapsed, dying right before her eyes.

“Take the Hoffs’ car outside,” Fleck directed some of his men, “and bring up our two cars at once. Carter and I’ll guard the prisoners until you get back. There’s a county jail only a few miles away. The sooner we get them there the better it will be. It won’t take any court long to settle their fate. They got Dean, didn’t they?”

“Yes,” said Jane, getting up unsteadily from the floor, “I think he’s dead.”

Fleck bent to examine the body of his aide, feeling for the pulse.

“Too bad,” he murmured. “That last bullet of old Hoff’s got him, but he died in a good cause.”

Jane, brushing away the tears that came welling unbidden into her eyes, turned now for the first time since his surrender to look at Frederic.

She had expected as she looked at him lying there shackled on the floor to read in his expression humiliation at his plight, grief at the failure of his effort to aid Germany, possibly reproach for her in having aided in entrapping him. To her amazement there was nothing of this in his face.

As he lay there on the floor he was observing her with a tender look of love, and in his eyes what was still more puzzling was an unmistakable expression of triumph and happiness.

CHAPTER XVII SOMETHING UNEXPECTED

Bewildered by the rapidity with which such a succession of terrifying events had taken place, Jane sank dazedly into a chair, trying her best to collect her thoughts, as she looked about on the recent scene of battle. All of the German plotters had been overcome and captured. There, dead on the floor, lay the arch conspirator, old Otto Hoff, his clammy face still twisted into a savage expression of malignant, defiant hate.

And there, too, a martyr to the country’s cause, lay Thomas Dean. A sob of pity rose in Jane’s throat as she thought of him, and the great tears rolled unchecked down her cheeks. He was so young, so brave, so fine. Why must Death have come to him when there was yet so much he might have done? With his talent and education, with his wonderful spirit of self-sacrifice, he might have gone far and high. Regretfully, she recalled that he had loved her, and with kind pity in her heart she reproached herself for not having been able to return to this fine, clean, American youth the affection she had inspired in him.

Thomas Dean, she told herself, was the type of man she should have loved, a man of her own people, with her own ideals, a man of her country, her flag, and yet—

There on the floor, not a dozen feet away from her, shameful circlets of steel girdling both his wrists and his ankles, lay the one man for whom she knew now she cared the most in all the world, the man she had just betrayed into Chief Fleck’s hands.

Bitterly she reproached herself for not having tried to induce Frederic to escape. In mental anguish she pictured him—the man she loved—standing in the prisoner’s dock in some courtroom, branded as a spy, as a leader of spies, charged with an attempt to slaughter the inhabitants—the women and children—of a sleeping, unprotected city. With growing horror it came to her that in all probability she herself would be called on to testify against him. It might even be her evidence that would result in his being led out before a firing squad and put to an ignominious death.

She dared not even look in his direction now. What must he be thinking about her? He had known that she loved him. In despair and doubt she wondered whether he could understand that she, too, had been influenced to perform her soul-wracking task by a sense of honor, of duty to her country equally as potent as that which had impelled him to participate in this terrible plan to destroy New York. Why had she not informed him that his plans were known to the United States Government’s agents? Surely she could have convinced him that his was a hopeless mission. The plot would have been successfully thwarted, and he would not be lying there in shackles, but, even though forced to flee, who knew, perhaps some day after peace had come, he might have been able to return for her. A great sob rose from her heart, but she stifled it back. She would be brave and true. She must be glad for those of her people that had been saved.

But her parents! What would they say? Her father and mother soon now must learn that she had been deceiving them day after day. How horrified and amazed they would be to learn that the chauffeur she had brought into the household was in reality a government detective, and that she, their daughter, had been a witness of his tragic death. What would they think when they learned about her part in this gruesome drama that had just been enacted? They, serene in their trust in her, supposing she was at the home of one of her girl friends, were peacefully asleep in their quiet apartment. How horror-stricken her mother would be if she could have seen her daughter at this moment, alone at midnight in a mountain shack, one girl among a band of strange men—and two men stretched dead on the floor.

And Frederic! Always her perturbed imaginings led back to Frederic, to the terrible fate that lay in store for him, to the awfulness of war that had put between them an impassable gulf of blood and guilt and treachery that, in spite of their love for each other, kept them at cross purposes and made them enemies. Why, she vaguely wondered, must governments disagree and start wars and make men hate and kill each other? What was it all for?

In the midst of her mental wanderings she became conscious that Fleck was speaking to Carter.

“I’ll stay here with Miss Strong and the prisoners,” he was saying. “While we are waiting for the men to return with the cars, you’d better make a search of the house.”

“Why not wait until daylight for that?” suggested Carter.

“It is not safe,” the chief objected. “To-night is the time to do it. A plot important enough to have the especial attention of the war office in Berlin must have many important persons involved in it. Somebody with money in New York, some influential German sympathizer, must have helped old Hoff set up these aeroplanes here and equip his shop. Some chemical plant supplied the material for those bombs. It must have taken hundreds of thousands of dollars to carry the plan to completion. Men rich enough and powerful enough to have put through this plot are powerful enough to be still dangerous. The minute word reaches the city that the plan has miscarried there will be some one up here posthaste to destroy or remove any damaging evidence we may have overlooked. Now is the time to do our searching.”

“You’re right, Chief,” Carter admitted. “It would not surprise me if there is not a wireless plant here. I’ll soon find out.”

“Let me help,” cried Jane.

Her nerves were suffering from a sharp reaction. All through the excitement of the attack she had remained calm and collected, but now she felt that if she remained another minute in the same room with the two bodies, if she stayed near that row of shackled prisoners, if she should chance to catch Frederic’s eye, she either would burst into hysterical weeping or would collapse entirely. If only there was some activity in which she could engage it might serve to divert the current of maddening thoughts that kept overwhelming her. With something to do she might regain her self-control.

“Please let me help Mr. Carter,” she begged.

“Certainly,” said Fleck, “go ahead. You have earned the right to do anything you wish to-night.”

Guided by the light of an electric torch Carter and she quickly made their way to the upper floor. In most of the rooms they found only cheap cots with blankets, evidently the sleeping quarters of the workmen, but in one of the rooms was a desk, and from it a ladder led to an unfinished attic. Boldly climbing the ladder and flashing their torch about they quickly located a high-powered wireless outfit. It was mounted on a sliding shelf by which it could be quickly concealed in a secret cupboard, but evidently the plotters had felt so secure from intrusion in their retreat that they had been in the habit of leaving it exposed.

“I thought we’d find it,” said Carter exultantly. “It’s an ideal location, up here in the mountains. I’d better smash it at once.”

“Wait,” warned Jane, thoughtfully, “they spoke of having received a wireless message from those dreadful X-boats lying there off the coast. If we could only find their code-book, perhaps—”

“Right,” cried Carter, catching her idea at once.

Together they descended to the room below and began ransacking the desk, Jane holding the light while Carter examined the papers they found.

“Their system sometimes is bad for them,” said Carter. “Here’s a ledger with the names of all the men employed here and the amounts paid to each. And look,” he went on excitedly, “look what the stupid fools have done with their German methodicalness—here are entries showing all the supplies they obtained, from whom they got them and what they cost. There’s evidence here for a hundred convictions. We’ll just take that book along.”

There was one small drawer in the desk that was locked. Ruthlessly Carter smashed the woodwork and pried it open. Its only contents was a small parcel, a folded paper in a parchment envelope. Hastily he drew forth the paper and studied it intently.

“It’s a code,” he cried, “a naval code, evidently the very one they used to communicate with those boats. I’ll wager the Washington people even haven’t a copy of it. That’s a great find. Come on, we’ve got enough for one night.”

“Do any of the men in our party understand wireless?” asked Jane as they descended.

“Sure,” said Carter, “Sills does. He used to be the radio man on a battleship.”

“Couldn’t he be left on watch here?” suggested Jane, “and try to signal those X-boats and keep them waiting until to-morrow night? Maybe by that time our—”

“I get you,” cried Carter; “that’s a good idea. Explain it to the Chief.”

As Jane unfolded her plan, suggesting the possibility of sending American cruisers out to search for the X-boats after Sills had lured them by false messages to the surface, Fleck heartily approved of it.

“I’ll leave Sills here with one other man to guard the house,” he said. “We’ll have to let poor Dean’s body remain here for the present, too. We’ll need all the room in the cars for the prisoners.”

There was still much to be done. While some of the men were unceremoniously carrying out the shackled prisoners and piling them in the cars, others, under Carter’s direction, crippled the three “wonder-workers” and dismantled them, carrying their dangerous cargo of bombs into the woods and concealing them.

None of the prisoners, since the moment the shackles had been put on, had uttered a word. Sullen silence held all of them unprotestingly in its grip. Even Frederic kept his peace, though from time to time his glance roved about, seeking Jane, and always in his eyes was a strange look, not of defeat, nor of shame, but rather of exultant triumph. Jane still dared not trust herself to look in his direction, but Fleck and Carter, too, observed curiously the expression in his eyes. Was he, they wondered, rejoicing over Dean’s untimely end? Did he, with true Prussian arrogance, in spite of the failure of his plot, still dare to hope that with Dean out of the way, he might escape punishment and yet win Jane Strong? Even as they picked him up, the last of the prisoners, and put him in the rear seat of the chief’s car, his eyes still sought for Jane.

It was long after midnight before the strange cavalcade left the mountain shack. Fleck’s car led the way, with the chief himself at the wheel, and Jane beside him. Crowded on the rear seat were Frederic and two other prisoners, and standing in the tonneau, facing them with his revolver drawn in case they should make an attempt to escape in spite of their shackles, was Fleck’s chauffeur. Carter was at the wheel of the second car with five prisoners and a man on guard, and the arrangement in the third car was the same. Six men and a girl to transport thirteen prisoners! Inwardly Fleck was congratulating himself on his forethought in having provided shackles enough to go around, for otherwise he surely would have had a perilous job on his hands.

As they rode down the mountain lane, Jane rejoiced at the darkness that hid her face, both from Fleck and from Frederic on the seat behind. Now that there was no activity to distract her maddening thoughts once more paced in turmoil through her brain. She loved this man, and she was leading him to disgrace and death. She hated and despised him. He was a treacherous, dangerous enemy of her country whom she had helped to trap, and she was glad, glad, glad. No, no! She wasn’t glad. She loved him. He had given her that sealed packet and had charged her to keep it for him. He couldn’t be all bad. Why must she love him? Her mind told her he was a criminal, an enemy, a spy, a murderer, yet her wilful heart insisted that she loved him. How strange life was! She and Frederic loved each other. Why could they not marry and be happy? Why was War? Why must nations fight? Why must people hate each other? Was the whole world mad? Was she going mad herself?

Slowly and carefully, Fleck, with his lights on full, had steered the automobile down the narrow roadway through the woods. He had just turned the car safely into the main road, and stopped to look back to see how closely the other cars were following. Suddenly from the wayside a dozen men in uniform sprang up, the glint of their guns made visible by the automobile lights.

“Halt,” cried a voice of authority.

The one glimpse he had caught of the uniform had conveyed to Fleck the welcome fact that the party surrounding him were Americans—cavalry troopers.

“Chief Fleck,” he announced, by way of identification. “Who are you?”

A tall figure in officer’s clothes sprang up on the running board and peered into Fleck’s face.

“Thank God, Chief,” he said, “that it’s you.”

“Colonel Brook-White,” cried Fleck in amazement, recognizing the voice as that of one of the officers in charge of the British Government’s Intelligence Service in America. “What are you doing here?”

“Trying to round up some bally German spies,” explained Brook-White.

“I’ve beaten you to it,” cried Fleck, with a note of triumph in his tone. “I’ve got them all here in shackles.”

“Good,” said Brook-White delightedly. “I was fearful I’d be too late. There was delay in getting a message to me. As soon as I had it, I tried to reach you and couldn’t. I dared not wait but dashed up here in my car. I knew there were some American troopers camped near here, and I persuaded the commander to detail some of his men to help me. Did you really capture the Hoff chap, old Otto?”

“He’s better than captured,” said Fleck. “He’s lying dead back there in the house.”

“Good,” cried Brook-White. “He was infernally dangerous according to my advices—but Captain Seymour—where is he? Wasn’t he working with you?”

“Captain Seymour?” cried Fleck in astonishment. “I never heard of him. Who’s Captain Seymour?”

“He’s one of my chaps,” explained Brook-White. “Wasn’t it he who steered you up here?”

“I should say not,” said Fleck emphatically.

“Good Lord,” cried the British colonel excitedly. “You don’t suppose those bloody Boches got him at the last—after all he’s been through? I hope he’s safe.”

“Don’t worry, Colonel Brook-White,” came the calm voice of Frederic Hoff from the rear seat. “Chief Fleck has me here safe in shackles with the other prisoners.”

“God,” cried Fleck, in astonished perplexity. “Is Frederic Hoff a Britisher—one of your men?”

“Rather,” said Brook-White. “Chief Fleck, may I present Captain Sir Frederic Seymour, of the Royal Kentish Dragoons.”

But Fleck was too busy just then to heed the introduction, or to pay attention to the muttered “Donnerwetters” of indignation that burst from the lips of his other prisoners.

Jane Strong had fainted dead away against his shoulder.

CHAPTER XVIII WHAT THE PACKET CONTAINED — THE END

“But,” said Jane, “I can’t understand it yet. How did you, a British officer, happen to be living with old Otto Hoff? How did you ever get him to trust you with his terrible secrets?”

Captain Seymour chortled gleefully. Now that he was arrayed in proper British clothes, once more comfortable in the uniform of his regiment and had his monocle in place and was with Jane again, everything looked radiantly different. Even his speech no longer retained its international quality but now was tinctured with London mannerisms.

“Oh, I say,” he replied, “that was a ripping joke on the bally Dutchmen.”

Jane eyed him uncertainly. He seemed almost like a stranger to her in this unfamiliar guise, though for hours she had been eagerly looking forward to his coming.

The exciting developments of the night before still were to her very puzzling. She recalled Frederic’s identification of himself, and after that all was blank. When she had come to she had found herself in a motor being rapidly driven toward New York in the early dawn, with Carter as her escort. He had not been inclined to be at all communicative.

“Let the Captain tell you the story himself,” said Carter. “He knows all the details.”

“But when can I see him?” questioned Jane. “When,” she hesitated, remembering the shameful bonds that had held him, “when will he be free?”

“He’s as free this minute as we are,” Carter explained. “It didn’t take the Chief long to get the bracelets off, after Colonel Brook-White had identified him. There’s a lot for the Captain to do still, but rest assured, he’ll waste no time getting back to the city to see you.”

“I hope not,” sighed the girl.

She was too weary, too weak from the revulsion of feeling that had come on learning that her lover instead of being a dastardly spy was a wonderful hero, to make even a pretense at maidenly modesty. She wanted to see Frederic too much to care what any one thought.

Slipping into her home fortunately without arousing any of her family, she had gone to bed with the intention of getting a rest of an hour or two. Sleep, she was sure, would be impossible, for she felt far too excited and upset. Yet she had not realized how utterly exhausted she was. Hardly had her head touched the pillow before she was lost to everything, and it was long after noon when a maid aroused her to announce that Captain Seymour had ’phoned that he would call at three.

As she dressed to receive him, she was wondering how she should greet him. Blushingly she recalled the impassioned kiss he had pressed on her lips—why it was only yesterday. It had seemed ages and ages ago, so much had intervened. Mingled with a shyness that arose from her vivid memories was also a shade of indignation. Why had he not told her? Did he not trust her? She resolved to punish him for not taking her into his confidence by an air of coldness toward him. Certainly he deserved it.

Yet, when he arrived, so full of animation did he appear to be, that the lofty manner in which she greeted him apparently went unnoticed. He met her with a warm handclasp and anxious inquiries about how she felt after all the exciting events. Too filled with eagerness to know all the details of his adventures she had found it difficult to maintain her pose, and soon was seated cosily beside him, asking him question after question, all the while furtively studying him in his proper rôle. As Frederic Hoff she had thought him wonderfully handsome and masterful. As Captain Sir Frederic Seymour, in his regimental finery, he was simply irresistible.

“A joke?” she repeated. “Do explain, I’m dying to know all about it.”

“It wasn’t half as difficult a job as one might imagine, you know. Our censor chaps at home have got to be quite expert at reading letters, invisible ink and all that sort of thing. Hoff for months had been sending cipher messages to the war office in Berlin. He kept urging them to act on his all-wonderful plan for blowing up New York. They decided finally to try it and notified old Otto they were sending over an officer to supervise the job.”

“What became of him? The officer they sent over?”

“Our people picked him off a Scandinavian boat and locked him up. They took his papers and turned them over to me. Clever, wasn’t it?”

“And you took his name and his papers and came here in his place? Oh, that was a brave, brave thing to do.”

“I wouldn’t say that,” said Seymour modestly. “I fancy I look a bit like the chap, and I speak the language perfectly.”

“But it was such a terrible risk to take,” cried Jane with a shudder. “Suppose they’d found you out?”

“No danger of that,” laughed Frederic. “Old Otto never had seen the chap who was coming. His real nephew, Frederic Hoff, whose American birth certificate was used, died years ago. Besides I had the German officer’s papers and knew just what his instructions were. The worst of it was when old Otto insisted every night on toasting the Kaiser, and when he kept trying to get me mixed up in his dirty schemes. I had to go through with the former once in a while, but on the latter, I—how do you Americans say it—just stalled along. My orders were to land him only on the big thing—his wonder-workers.”

“But how did you explain to him that British uniform?”

“Now that was really an idea. The old fellow was getting a bit cross and suspicious with me because he thought I wasn’t doing enough while they were getting his ‘wonder-workers’ ready. At one time he was so distrustful of me that he had me followed.”

“Oh, yes, I know,” said Jane quickly. With a thrill she remembered the scene she had witnessed from her window the night K-19, her predecessor on Chief Fleck’s staff, had been murdered. In her relief at discovering that Frederic was no German spy, she had forgotten that for weeks and weeks she had all but believed him guilty of murder. Now, something told her, surely and confidently, that he could explain it all.

“I saw you from my window one night before I met you,” she went on. “A man was following you, and you chased him around the corner.”

“I remember that,” he said; “the poor chap was found dead the next morning. Old Otto killed him. The man had been following me, and I had imagined that he was one of old Otto’s spies and knocked him down. I couldn’t find anything on him to indicate who he was, so just as he was beginning to revive I left him and came on home. It seems old Otto had been watching him trail me. He followed along and shot the man. He gleefully told me about it the next day, the hound. I ought to have given him over to the police, but that would have upset our plans.”

“I see,” said Jane; “what about Lieutenant Kramer? Was he working with old Mr. Hoff?”

“That’s the funny part of it. Here in this country you’ve got so many kinds of secret agents they’re always trampling on each others’ toes. There’s your treasury agents, and your Department of Justice agents, and your army intelligence men and your naval intelligence men—nine different sets of investigators you’ve got, counting the volunteers, so some one told me, and each lot trying to make a record for itself and not taking the others into its confidence. Rather stupid I call it.”

“I should say so,” agreed Jane.

“Here was I watching old Hoff for our government, and Kramer watching me for your navy and Fleck watching both of us. It was a funny jumble.”

“But about that uniform?” Jane persisted.

“When the old man got to ragging me a bit, I felt I must do something to convince him I was all right. I suggested trying to get a British uniform and maybe learning thereby some secrets. It delighted him hugely. Of course I just went down to Colonel Brook-White and got my own uniform, and that was all there was to that.”

“It puzzled Mr. Carter, though, how you got it in and out of the house. He used to open every bundle that came for Mr. Hoff.”

Sir Frederic laughed delightedly.

“I had a messenger who used to bring it back and forth in a big lady’s hat-box. It always was addressed to you, my dear, but the boy had instructions to deliver it to me.”

“Humph,” snapped Jane with mock indignation. “And when did you first find out that I was helping Chief Fleck watch you?”

“I suspected it from the start. Kramer told me how you’d become acquainted with him. Then when I heard you ’phoning Carter about the bookstore I knew for certain.”

“Oh, that’s one thing now I wanted to ask about—those messages Hoff left in the bookstore. Who were they for?”

“Instructions to a German advertising agency on how to word some advertisements that contained a code.”

“Oh, those Dento advertisements?”

“You knew about them?” cried Seymour in astonishment.

“Of course,” said Jane proudly. “I was the one who deciphered them; but what did that girl do with those messages? Carter had a theory that she slipped them under a dachshund’s collar.”

“That theory’s just like Carter,” laughed Frederic—“regular detective stuff. I never heard of any dachshund’s being used. The girl used to slip them into a letter box in her apartment-house hallway. Two minutes later a man would get them and carry them to their destination.”

“The traitors in our navy—the men who signalled old Otto and Lena Kraus about the transports—who were they? They are the scoundrels I’d like to see arrested and shot.”

“Never worry. They’ll all meet their deserts. I can’t tell even you who they are, but I’ve given your Chief Fleck a list of them. They will be quickly rounded up now. What else can I tell you?”

“There’s this,” said Jane, the color rising to her cheeks as she drew forth from its hiding place in the bosom of her gown the packet he had entrusted to her the morning before, its seals still intact.

“What?” he cried in delight. “You kept it safe? You did not open it even when you saw me arrested, when you must have been convinced that I was a spy? Girl, dear girl”—his voice became a caress, and the light of love flamed up in his eyes, “you did trust me then, in spite of everything.”

“I had promised you, and I kept my promise,” faltered Jane, striving for words to explain, though she had been unable to explain her actions even to herself. “I think my heart trusted you all the time, even though my head and eyes made me believe you were what you pretended to be. Even when things looked blackest my heart persisted that you were true.”

“God bless your heart for that,” cried Frederic, as he took the little packet from her hands and began breaking the seals. “Yesterday morning, when old Otto’s plans were ready, I foresaw the danger of the trip ahead of me. I realized I might never come back alive. If they discovered who I was a second too soon it would mean my death. I dared not, for my country’s sake, tell even you what I was doing. My honor was at stake. I dared not drop the slightest hint nor write a single line. The only thing I’d kept about me in the apartment that wasn’t filthy German stuff was what’s in here.”

Slowly he was unwrapping something rolled in tissue paper, as Jane, eager-eyed, looked wonderingly on.

“But,” he went on, “I couldn’t go away from you without leaving some token, some clue. If it happened that I never came back, I wanted you to know—”

He stopped abruptly.

“To know what?” questioned the girl breathlessly.

“To know that I loved you, darling, better than all else save honor,” he said, taking her into his arms. “See the token I left behind for you. It’s an old, old family ring with the Seymour crest. You’ll wear it, girl of mine, won’t you, wear it always.”

Unhesitatingly Jane Strong thrust forth the third finger on her left hand, and instinctively her lips turned upward toward his.

And no matter what might have happened just then in the apartment next door, neither of them would have known anything about it.

The Apartment Next Door — by William Johnston — AUTHOR OF — THE HOUSE OF WHISPERS, LIMPY, ETC. — ARTHUR WILLIAM BROWN — 1919 — TO THAT MARVELLOUS SCHEHERAZADE — CAROLYN WELLS HOUGHTON — THE AUTHOR, IN ENVIOUS ADMIRATION, — DEDICATES THIS VOLUME

ILUSTRATIONS BY

CONTENTS

LIST OF ILLUSTRATIONS

THE APARTMENT NEXT DOOR

CHAPTER I THE FACE OF HATE

CHAPTER II THE ADDRESS ON THE CARD

CHAPTER III “MR. FLECK”

CHAPTER IV THE CLUE IN THE BOOK

CHAPTER V ON THE TRAIL

CHAPTER VI THE MISSING MESSAGE

CHAPTER VII THE WOMAN ON THE ROOF

CHAPTER VIII THE LISTENING EAR

CHAPTER IX THE PURSUIT

CHAPTER X CARTER’S DISCOVERY

CHAPTER XI JANE’S ADVENTURE

CHAPTER XII PUZZLES AND PLANS

CHAPTER XIII THE SEALED PACKET

CHAPTER XIV THE MOUNTAIN’S SECRET

CHAPTER XV THE HOUSE IN THE WOODS

CHAPTER XVI THE ATTACK ON THE HOUSE

CHAPTER XVII SOMETHING UNEXPECTED

CHAPTER XVIII WHAT THE PACKET CONTAINED — THE END