Baron de Grost glanced at the card which his butler had brought in to him, carelessly at first, afterwards with that curious rigidity of attention which usually denotes the setting free of a flood of memories.

"The gentleman would like to see you, sir," the man announced.

"You can show him in at once," Peter replied.

The servant withdrew. Peter, during those few minutes of waiting, stood with his back to the room and his face to the window, looking out across the square, in reality seeing nothing, completely immersed in this strange flood of memories. John Dory—Sir John Dory now—a quondam enemy, whom he had met but seldom during these later years. The figure of this man, who had once loomed so largely in his life, had gradually shrunk away into the background. Their avoidance of each other arose, perhaps, from a sort of instinct which was certainly no matter of ill-will. Still, the fact remained that they had scarcely exchanged a word for years, and Peter turned to receive his unexpected guest with a curiosity which he did not trouble wholly to conceal.

Sir John Dory—Chief Commissioner of Scotland Yard, a person of weight and importance—had changed a great deal during the last few years. His hair had become grey, his walk more dignified. There was the briskness, however, of his best days in his carriage, and in the flash of his brown eyes. He held out his hand to his ancient foe with a smile.

"My dear Baron," he said, "I hope you are going to say that you are glad to see me."

"Unless," Peter replied, with a good-humoured grimace, "your visit is official, I am more than glad—I am charmed. Sit down. I was just going to take my morning cigar. You will join me? Good! Now I am ready for the worst that can happen."

The two men seated themselves. John Dory pulled at his cigar appreciatively, sniffed its flavour for a moment, and then leaned forward in his chair.

"My visit, Baron," he announced, "is semi-official. I am here to ask you a favour."

"An official favour?" Peter demanded quickly.

His visitor hesitated, as though he found the question hard to answer.

"To tell you the truth," he declared, "this call of mine is wholly an inspiration. It does not in any way concern you personally, or your position in this country. What that may be I do not know, except that I am sure it is above any suspicion."

"Quite so," Peter murmured. "How diplomatic you have become, my dear friend!"

John Dory smiled.

"Perhaps I am fencing about too much," he said. "I know, of course, that you are a member of a very powerful and wealthy French society, whose object and aims, so far as I know, are entirely harmless."

"I am delighted to be assured that you recognise that fact," Peter admitted.

"I might add," John Dory continued, "that this harmlessness is of recent date."

"Really, you do seem to know a good deal," Peter confessed.

"I find myself still fencing," Dory declared. "A matter of habit, I suppose. I didn't mean to when I came. I made up my mind to tell you simply that Guillot was in London, and to ask you if you could help me to get rid of him."

Peter looked thoughtfully into his companion's face, but he did not speak. He understood at such moments the value of silence.

"We speak together," Dory continued softly, "as men who understand one another. Guillot is the one criminal in Europe whom we all fear; not I alone, mind you—it is the same in Berlin, in Petersburg, in Vienna. He has never been caught. It is my honest belief that he never will be caught. At the same time, wherever he arrives the thunderclouds gather. He leaves behind him always a trail of evil deeds."

"Very well put," Peter murmured. "Quite picturesque."

"Can you help me to get rid of him?" Dory inquired. "I have my hands full just now, as you can imagine, what with the political crisis and these constant mass meetings. I want Guillot out of the country. If you can manage this for me I shall be your eternal debtor."

"Why do you imagine," Peter asked, "that I can help you in this matter?"

There was a brief silence. John Dory knocked the ash from his cigar.

"Times have changed," he said. "The harmlessness of your great society, my dear Baron, is at present admitted. But there were days——"

"Exactly," Peter interrupted. "As shrewd as ever, I perceive. Do you know anything of the object of his coming?"

"Nothing."

"Anything of his plans?"

"Nothing."

"You know where he is staying?"

"Naturally," Dory answered. "He has taken a second-floor flat in Crayshaw Mansions, Shaftesbury Avenue. As usual, he is above all petty artifices. He has taken it under the name of Monsieur Guillot."

"I really don't know whether there is anything I can do," Peter decided, "but I will look into the matter for you with pleasure. Perhaps I may be able to bring a little influence to bear—indirectly, of course. If so, it is at your service. Lady Dory is well, I trust?"

"In the best of health," Sir John replied, accepting the hint and rising to his feet. "I shall hear from you soon?"

"Without a doubt," Peter answered. "I must certainly call upon Monsieur Guillot."

Peter wasted no time in paying his promised visit. That same afternoon he rang the bell at the flat in Crayshaw Mansions. A typical French butler showed him into the room where the great man sat. Monsieur Guillot, slight, elegant, preeminently a dandy, was lounging upon a sofa, being manicured by a young lady. He threw down his Petit Journal and rose to his feet, however, at his visitor's entrance.

"My dear Baron," he exclaimed, "but this is charming of you! Mademoiselle," he added, turning to the manicurist, "you will do me the favour of retiring for a short time. Permit me."

He opened the door and showed her out. Then he came back to Peter.

"A visit of courtesy, Monsieur le Baron?" he asked.

"Without a doubt," Peter replied.

"It is beyond all measure charming of you," Guillot declared, "but let me ask you a question. Is it peace or war?"

"It is what you choose to make it," Peter answered.

The man threw out his hands. There was the shadow of a frown upon his pale forehead. It was a matter for protest, this.

"Why do you come?" he demanded. "What have we in common? The society has expelled me. Very well, I go my own way. Why not? I am free of your control to-day. You have no more right to interfere with my schemes than I with yours."

"We have the ancient right of power," Peter said grimly. "You were once a prominent member of our organisation, the spoilt protÉgÉ of madame, a splendid maker, if you will, of criminal history. Those days have passed. We offered you a pension which you have refused. It is now our turn to speak. We require you to leave this city in twenty-four hours."

The man's face was livid with anger. He was of the fair type of Frenchman, with deep-set eyes, and a straight, cruel mouth only partly concealed by his golden moustache. Just now, notwithstanding the veneer of his too perfect clothes and civilised air, the beast had leapt out. His face was like the face of a snarling animal.

"I refuse!" he cried. "It is I who refuse! I am here on my own affairs. What they may be is no business of yours or of anyone else's. That is my answer to you, Baron de Grost, whether you come to me for yourself or on behalf of the society to which I no longer belong. That is my answer—that and the door," he added, pressing the bell. "If you will, we fight. If you are wise, forget this visit as quickly as you can."

Peter took up his hat. The man-servant was already in the room.

"We shall probably meet again before your return, Monsieur Guillot," he remarked.

Guillot had recovered himself. His smile was wicked, but his bow perfection.

"To the fortunate hour, Monsieur le Baron!" he replied.

Peter drove back to Berkeley Square, and without a moment's hesitation pressed the levers which set in work the whole underground machinery of the great power which he controlled. Thence-forward Monsieur Guillot was surrounded with a vague army of silent watchers. They passed in and out even of his flat, their motor-cars were as fast as his in the streets, their fancy in restaurants identical with his. Guillot moved through it all like a man wholly unconscious of espionage, showing nothing of the murderous anger which burned in his blood. The reports came to Peter every hour, although there was, indeed, nothing worth chronicling. Monsieur Guillot's visit to London would seem, indeed, to be a visit of gallantry. He spent most of his time with Mademoiselle Louise, the famous dancer. He was prominent at the Empire to watch her nightly performance; they were a noticeable couple supping together at the Milan afterwards. Peter smiled as he read the reports. Monsieur Guillot was indeed a man of gallantry, but he had the reputation of using these affairs to cloak his real purpose. Those who watched him watched only the more closely. Monsieur Guillot, who stood it very well at first, unfortunately lost his temper. He drove to Berkeley Square in the great motor-car which he had brought with him from Paris, and confronted Peter.

"My friend," he exclaimed, though, indeed, the glitter in his eyes knew nothing of friendship, "it is intolerable, this! Do you think that I do not see through these dummy waiters, these obsequious shopmen, these ladies who drop their eyes when I pass, these commissionaires, these would-be acquaintances? I tell you that they irritate me, this incompetent, futile crowd. You pit them against me! Bah! You should know better. When I choose to disappear, I shall disappear, and no one will follow me. When I strike, I shall strike, and no one will discover what my will may be. You are out of date, dear Baron, with your third-rate army of stupid spies. You succeed in one thing only—you succeed in making me angry."

"It is at least an achievement, that," Peter declared.

"Perhaps," Monsieur Guillot admitted fiercely. "Yet mark now the result. I defy you, you and all of them. Look at your clock. It is five minutes to seven. It goes well, that clock, eh?"

"It is the correct time," Peter said.

"Then by midnight," Guillot continued, shaking his fist in the other's face, "I shall have done that thing which brought me to England, and I shall have disappeared. I shall have done it in spite of your watchers, in spite of your spies, in spite, even, of you, Monsieur le Baron de Grost. There is my challenge. VoilÀ. Take it up if you will. At midnight you shall hear me laugh. I have the honour to wish you good night!"

Peter opened the door with his own hands.

"This is excellent," he declared. "You are now, indeed, the Monsieur Guillot of old. Almost you persuade me to take up your challenge."

Guillot laughed derisively.

"As you please!" he exclaimed. "By midnight to-night!"

The challenge of Monsieur Guillot was issued precisely at four minutes before seven. On his departure, Peter spent the next half-hour studying certain notes and sending various telephone messages. Afterwards he changed his clothes at the usual time and sat down to a tÊte-À-tÊte dinner with his wife. Three times during the course of the meal he was summoned to the telephone, and from each visit he returned more perplexed. Finally, when the servants had left the room, he took his chair round to his wife's side.

"Violet," he said, "you were asking me just now about the telephone. You were quite right. These were not ordinary messages which I have been receiving. I am engaged in a little matter which, I must confess, perplexes me. I want your advice—perhaps your help."

Violet smiled.

"I am quite ready," she announced. "It is a long time since you gave me anything to do."

"You have heard of Guillot?"

She reflected a moment.

"You mean the wonderful Frenchman," she asked, "the head of the criminal department of the Double Four?"

"The man who was at its head when it existed," Peter replied. "The criminal department, as you know, has all been done away with. The Double Four has now no more concern with those who break the law, save in those few instances where great issues demand it."

"But Monsieur Guillot still exists?"

"He not only exists," Peter answered, "but he is here in London, a rebel and a defiant one. Do you know who came to see me the other morning?"

She shook her head.

"Sir John Dory," Peter continued. "He came here with a request. He begged for my help. Guillot is here, committed to some enterprise which no man can wholly fathom. Dory has enough to do with other things, as you can imagine, just now. Besides, I think he recognises that Monsieur Guillot is rather a hard nut for the ordinary English detective to crack."

"And you?" she demanded, breathlessly.

"I join forces with Dory," Peter admitted. "Sogrange agrees with me. Guillot was associated with the Double Four too long for us to have him make scandalous history, either here or in Paris."

"You have seen him?"

"I have not only seen him," Peter said, "I have declared war against him."

"And he?"

"Guillot is defiant," Peter replied. "He has been here only this evening. He mocks at me. He swears that he will bring off this enterprise, whatever it may be, before midnight to-night, and he has defied me to stop him."

"But you will," she murmured softly.

Peter smiled. The conviction in his wife's tone was a subtle compliment which he did not fail to appreciate.

"I have hopes," he confessed, "and yet, let me tell you this, Violet, I have never been more puzzled. Ask yourself, now. What enterprise is there worthy of a man like Guillot, in which he could engage himself here in London between now and midnight? Any ordinary theft is beneath him. The purloining of the Crown jewels, perhaps, he might consider, but I don't think that anything less in the way of robbery would bring him here. He has his code and he is as vain as a peacock. Yet money is at the root of everything he does."

"How does he spend his time here?" Violet asked.

"He has a handsome flat in Shaftesbury Avenue," Peter answered, "where he lives, to all appearance, the life of an idle man of fashion. The whole of his spare time is spent with Mademoiselle Louise, the danseuse at the Empire. You see, it is half-past eight now. I have eleven men altogether at work, and according to my last report he was dining with her in the grillroom at the Milan. They ordered their coffee just ten minutes ago, and the car is waiting outside to take Mademoiselle to the Empire. Guillot's box is engaged there, as usual. If he proposes to occupy it, he is leaving himself a very narrow margin of time to carry out any enterprise worth speaking of."

Violet was thoughtful for several moments. Then she crossed the room, took up a copy of an illustrated paper, and brought it across to Peter. He smiled as he glanced at the picture to which she pointed, and the few lines underneath.

"It has struck you, too, then!" he exclaimed. "Good! You have answered me exactly as I hoped. Somehow, I scarcely trusted myself. I have both cars waiting outside. We may need them. You won't mind coming to the Empire with me?"

"Mind?" she laughed. "I only hope I may be in at the finish."

"If the finish," Peter remarked, "is of the nature which I anticipate, I shall take particularly good care that you are not."

The curtain was rising upon the first act of the ballet as they entered the music-hall and were shown to the box which Peter had engaged. The house was full—crowded, in fact, almost to excess. They had scarcely taken their seats when a roar of applause announced the coming of Mademoiselle Louise. She stood for a moment to receive her nightly ovation, a slim, beautiful creature, looking out upon the great house with that faint, bewitching smile at the corners of her lips which every photographer in Europe had striven to reproduce. Then she moved away to the music, an exquisite figure, the personification of all that was alluring in her sex. Violet leaned forward to watch her movements as she plunged into the first dance. Peter was occupied looking round the house. Monsieur Guillot was there, sitting insolently forward in his box, sleek and immaculate. He even waved his hand and bowed as he met Peter's eye. Somehow or other, his confidence had its effect. Peter began to feel vaguely troubled. After all, his plans were built upon a surmise. It was so easy for him to be wrong. No man would show his hand so openly who was not sure of the game. Then his face cleared a little. In the adjoining box to Guillot's the figure of a solitary man was just visible, a man who had leaned over to applaud Louise, but who was now sitting back in the shadows. Peter recognised him at once, notwithstanding the obscurity. This was so much to the good, at any rate. He took up his hat.

"For a quarter of an hour you will excuse me, Violet," he said. "Watch Guillot. If he leaves his place, knock at the door of your box, and one of my men, who is outside, will come to you at once. He will know where to find me."

Peter hurried away, pausing for a moment in the promenade to scribble a line or two at the back of one of his own cards. Presently he knocked at the door of the box adjoining Guillot's and was instantly admitted. Violet continued her watch. She remained alone until the curtain fell upon the first act of the ballet. A few minutes later Peter returned. She knew at once that things were going well. He sank into a chair by her side.

"I have messages every five minutes," he whispered in her ear, "and I am venturing upon a bold stroke. There is still something about the affair, though, which I cannot understand. You are absolutely sure that Guillot has not moved?"

Violet pointed with her programme across the house.

"There he sits," she remarked. "He left his chair as the curtain went down, but he could scarcely have gone out of the box, for he was back within ten seconds."

Peter looked steadily across at the opposite box. Guillot was sitting a little farther back now, as though he no longer courted observation. Something about his attitude puzzled the man who watched him. With a quick movement he caught up the glasses which stood by his wife's side. The curtain was going up for the second act, and Guillot had turned his head. Peter held the glasses only for a moment to his eyes, and then glanced down at the stage.

"My God!" he muttered. "The man's a genius! Violet, the small motor is coming for you."

He was out of the box in a single step. Violet looked after him, looked down upon the stage and across at Guillot's box. It was hard to understand.

The curtain had scarcely rung up upon the second act of the ballet when a young lady, who met from all the loungers, and even from the door-keeper himself, the most respectful attention, issued from the stage-door at the Empire and stepped into the large motor-car which was waiting, drawn up against the kerb. The door was opened from inside and closed at once. She held out her hands, as yet ungloved, to the man who sat back in the corner.

"At last!" she murmured. "And I thought that you had forsaken me. It seemed, indeed, dear one, that you had forsaken me."

He took her hands and held them tightly, but he answered only in a whisper. He wore a sombre black cloak and a broad-brimmed hat. A muffler concealed the lower part of his face. She put her finger upon the electric light, but he stopped her.

"I must not be recognised," he said thickly. "Forgive me, Louise, if I seem strange at first, but there is more in it than I can tell you. No one must know that I am in London to-night. When we reach this place to which you are taking me, and we are really alone, then we can talk. I have so much to say."

She looked at him doubtfully. It was indeed a moment of indecision with her. Then she began to laugh softly.

"Little one, but you have changed!" she exclaimed compassionately. "After all, why not? I must not forget that things have gone so hardly with you. It seems odd, indeed, to see you sitting there, muffled up like an old man, afraid to show yourself. You know how foolish you are? With your black cape and that queer hat, you are so different from all the others. If you seek to remain unrecognised, why do you not dress as all the men do? Anyone who was suspicious would recognise you from your clothes."

"It is true," he muttered. "I did not think of it."

She leaned towards him.

"You will not even kiss me?" she murmured.

"Not yet," he answered.

She made a little grimace.

"But you are cold!"

"You do not understand," he answered. "They are watching me—even to-night they are watching me. Oh, if you only knew, Louise, how I have longed for this hour that is to come!"

Her vanity was assuaged. She patted his hand, but came no nearer.

"You are a foolish little one," she said, "very foolish."

"It is not for you to say that," he replied. "If I have been foolish, were not you often the cause of my folly."

Again she laughed.

"Oh, la, la! It is always the same! It is always you men who accuse! For that presently I shall reprove you. But now—as for now, behold, we have arrived!"

"It is a crowded thoroughfare," the man remarked nervously, looking up and down Shaftesbury Avenue.

"Stupid!" she cried, stepping out. "I do not recognise you to-night, little one. Even your voice is different. Follow me quickly across the pavement and up the stairs. There is only one flight. The flat I have borrowed is on the second floor. I do not care very much that people should recognise me either, under the circumstances. There is nothing they love so much," she added, with a toss of the head, "as finding an excuse to have my picture in the paper."

He followed her down the dim hall and up the broad, flat stairs, keeping always some distance behind. On the first landing she drew a key from her pocket and opened a door. It was the door of Monsieur Guillot's sitting-room. A round table in the middle was laid for supper. One light alone, and that heavily shaded, was burning.

"Oh, la, la," she exclaimed. "How I hate this darkness! Wait till I can turn on the lights, dear friend, and then you must embrace me. It is from outside, I believe. No, do not follow. I can find the switch for myself. Remain where you are. I return instantly."

She left him alone in the room, closing the door softly. In the passage she reeled for a moment and caught at her side. She was very pale. Guillot, coming swiftly up the steps, frowned as he saw her.

"He is there?" he demanded harshly.

"He is there," Louise replied; "but, indeed, I am angry with myself. See, I am faint. It is a terrible thing, this, which I have done. He did me no harm, that young man, except that he was stupid and heavy, and that I never loved him. Who could love him, indeed? But, Guillot——"

He passed on, scarcely heeding her words, but she clung to his arm.

"Dear one," she begged, "promise that you will not really hurt him. Promise me that, or I will shriek out and call the people from the streets here. You will not make an assassin of me? Promise!"

Guillot turned suddenly towards her, and there were strange things in his face. He pointed down the stairs.

"Go back, Louise," he ordered, "back to your rooms, for your own sake. Remember that you left the theatre, too ill to finish your performance. You have had plenty of time already to get home. Quick! Leave me to deal with this young man. I tell you to go."

She retreated down the stairs, dumb, her knees shaking still as though with fear. Guillot entered the room, closing the door behind him. Even as he bowed to that dark figure standing in the corner, his left hand shot forward the bolt.

"Monsieur," he said.

"What is the meaning of this?" the visitor interrupted haughtily. "I am expecting Mademoiselle Louise. I did not understand that strangers had the right of entry into this room."

Guillot bowed low.

"Monsieur," he said once more, "it is a matter for my eternal regret that I am forced to intrude even for a moment upon an assignation so romantic. But there is a little matter which must first be settled. I have some friends here who have a thing to say to you."

He walked softly, with catlike tread, along by the wall to where the thick curtains shut out the inner apartment. He caught at the thick velvet, dragged it back, and the two rooms were suddenly flooded with light. In the recently discovered one, two stalwart-looking men in plain clothes, but of very unmistakable appearance, were standing waiting. Guillot staggered back. They were strangers to him. He was like a man who looks upon a nightmare. His eyes protruded. The words which he tried to utter failed him. Then, with a swift, nervous presentiment, he turned quickly around towards the man who had been standing in the shadows. Here, too, the unexpected had happened. It was Peter, Baron de Grost, who threw his muffler and broad-brimmed hat upon the table.

"Five minutes to eleven, I believe, Monsieur Guillot," Peter declared. "I win by an hour and five minutes."

Guillot said nothing for several seconds. After all, though, he had great gifts. He recovered alike his power of speech and his composure.

"These gentlemen," he said, pointing with his left hand towards the inner room. "I do not understand their presence in my apartments."

Peter shrugged his shoulders.

"They represent, I am afraid, the obvious end of things," he explained. "You have given me a run for my money, I confess. A Monsieur Guillot who is remarkably like you still occupies your box at the Empire, and Mademoiselle Jeanne LemÈre, the accomplished understudy of the lady who has just left us, is sufficiently like the incomparable Louise to escape, perhaps, detection for the first few minutes. But you gave the game away a little, my dear Guillot, when you allowed your quarry to come and gaze even from the shadows of his box at the woman he adored."

"Where is—he?" Guillot faltered.

"He is on his way back to his country home," Peter replied. "I think that he will be cured of his infatuation for Mademoiselle. The assassins whom you planted in that room are by this time in Bow Street. The price which others beside you knew, my dear Guillot, was placed upon that unfortunate young man's head will not pass this time into your pocket. For the rest——"

"The rest is of no consequence," Guillot interrupted, bowing. "I admit that I am vanquished. As for those gentlemen there," he added, waving his hand towards the two men, who had taken a step forward, "I have a little oath which is sacred to me concerning them. I take the liberty, therefore, to admit myself defeated, Monsieur le Baron, and to take my leave."

No one was quick enough to interfere. They had only a glimpse of him as he stood there with the revolver pressed to his temple, an impression of a sharp report, of Guillot staggering back as the revolver slipped from his fingers on to the floor. Even his death cry was stifled. They carried him away without any fuss, and Peter was just in time, after all, to see the finish of the second act of the ballet. The sham Monsieur Guillot still smirked at the sham Louise, but the box by his side was empty.

"Is it over?" Violet asked breathlessly.

"It is over," Peter answered.

It was, after all, an unrecorded tragedy. In an obscure corner of the morning papers one learned the next day that a Frenchman, who had apparently come to the end of his means, had committed suicide in a furnished flat in Shaftesbury Avenue. Two foreigners were deported without having been brought up for trial, for being suspected persons. A little languid interest was aroused at the inquest when one of the witnesses deposed to the deceased having been a famous French criminal. Nothing further transpired, however, and the readers of the halfpenny press for once were deprived of their sensation. For the rest, Peter received, with much satisfaction, a remarkably handsome signet ring, bearing some famous arms, and a telegram from Sogrange: "Well done, Baron! May the successful termination of your enterprise nerve you for the greater undertaking which is close at hand. I leave for London by the night train.—Sogrange."