"Listen, monsieur," Louis continued. "It is our pleasure to save you from the unpleasant consequences which would certainly have befallen you in any other place than the Cafe des Deux Epingles after your--shall we say misunderstanding?--with James Tapilow."

"I admit my indebtedness, Louis," I answered.

"Will you do something to repay it?" Louis asked, raising his eyes to mine.

"You will have to tell me what it is first," I said.

"It is concerned with the disappearance of Mr. Delora," Louis said.

"But Mr. Delora has returned!" I exclaimed. "His niece told me so herself. He has returned, but he is very unwell--confined to his room, I believe."

"It is the story which has been agreed upon," Louis answered. "We were obliged to protect ourselves against the police and the newspaper people, but, nevertheless, it is not the truth. Mr. Delora has not returned!"

"Does mademoiselle know that?" I asked quickly.

"She does not," Louis admitted. "She has been told exactly what she told you,--that her uncle had returned, but that he was ill and must be kept quiet for a little time. It was necessary that she should believe his room occupied, for reasons which you will understand later. She shall be told the truth very soon."

I was conscious of a distinct sense of relief. The thought that she might have told me a falsehood had given me a sudden stab.

"Where is Mr. Delora, then?" I asked.

"That we can guess," Louis said. "We want you to go to him."

"Very well, Louis," I said. "I am perfectly agreeable, only you must tell me who this Mr. Delora is, why he is in hiding, and who you mean when you say 'we'."

"Monsieur," Louis said, "if it rested with me alone I would tell you all these things. I would give you our confidence freely, because we are a little company who trust freely when we are sure. The others, however, do not know you as I know you, and I have the right to divulge only certain things to you. Mr. Delora has come to this country on a mission of peculiar danger. He has a secret in his possession which is of immense value, and there are others who are not our friends who know of it. Mr. Delora had a signal at Charing Cross that there was danger in taking up his residence here. That is why he slipped away quietly and is lying now in hiding. If monsieur indeed desires an adventure, I could propose one to him."

"Go ahead, Louis," I said.

"Let it be understood that Mr. Delora has returned.--As I have already told you, he has not returned. The door of his room is locked, and no one is permitted to enter. It is believed that to-night an attempt will be made to force a way into that room and to rob its occupant."

"The room is empty, you say? There is no one there?" I interrupted.

"Precisely, monsieur," Louis said, "but if some one were there who was strong and brave it might be possible to teach a lesson to those who have played us false, and who have planned evil things! If that some one were you, Captain Rotherby, we should consider--Monsieur Decresson and the others would consider--that your debt to them was paid!"

I whistled softly to myself. I began to see Louis' idea. I was to enter, somehow or other, the room in which Mr. Delora was supposed to be, to remain there concealed, and to await this attack which, for some reason or other, they were expecting. And then, as the possibilities connected with such an event spread themselves out before me, my sense of humor suddenly a.s.serted itself, and, to Louis'

amazement, I laughed in his face. I came back from this world of fanciful figures, of mysterious robberies, of attempted a.s.sa.s.sinations, to the world of every-day things. It was Louis--the _maitre d'hotel,_ the man who had ordered my _Plat du Jour_ and selected my Moselle--who spoke of these things so calmly in my own sitting-room, with a menu card in his hand, and a morocco-bound wine list sticking out of his breast pocket. I was not in any imaginary city but in London,--city of tragedies, indeed, but tragedies of a homelier sort. It was not possible that such things could be happening here, in an atmosphere which, through familiarity, had become almost commonplace. Was I to believe that Louis, my favorite _maitre d'hotel_, my fellow schemer in many luncheon and dinner parties, my authority upon vintages, my gastronomic good angel, was one of a band of conspirators, who played with life and death as though they had been the b.a.l.l.s of a juggler? Was I to believe that there existed even in this very hotel, which for years had been my home, the seeds of these real tragical happenings which sometimes, though only half disclosed, blaze out upon the world as a revelation of the great underground world of crime? I found it almost impossible to take Louis seriously. I could not focus my thoughts.

"Louis," I said, "is this a great joke, or are you talking to me in sober, serious earnest?"

"I am talking in earnest, monsieur," Louis said slowly. "I have not exaggerated or spoken a word to you which is not the truth."

"Let me understand this thing a little more clearly," I said. "What has Ferdinand Delora done that he need fear a murderous a.s.sault? What has he done to make enemies? Is he a criminal, or are those who seek him criminals?"

"He carries with him," Louis said slowly, "a secret which will produce a great fortune. There are others who think that they have a right to share in it. It is those others who are his enemies. It is those others who hope to attain by force what they could gain by no other means."

A sudden inspiration prompted my next question.

"Was Tapilow one of those?" I demanded.

Louis nodded gravely.

"Monsieur Tapilow was one of those who claimed a share, but he was not willing to run the smallest risk," he a.s.sented.

"And for that reason," I remarked, "he is well out of the way! I understand. There is one more question, Louis, and it is one which you must answer me truthfully. You can imagine what it is when I tell you that it concerns mademoiselle!"

"Mademoiselle is innocent of the knowledge of any of these things,"

Louis declared earnestly. "She is a very charming and a very beautiful young lady, but if ever a young lady needed friends, she does!"

"Why is she here at all?" I demanded. "Why was she not left behind in Paris? If there is no part for her to play in this little comedy, it seems to me that she would have been much better out of the way."

"Captain Rotherby," Louis said, "there was a reason, and some day you will understand it--why it was necessary that she should come to London with her uncle. I can tell you no more. You must not ask me any more."

I looked into Louis' impenetrable face. I could learn nothing there. His words had left me partly unconvinced. Somehow I felt that the only time he had spoken the entire truth was when he had spoken of Felicia. Yet it was certainly true that I owed these people something, and I had no wish to shrink from paying my debt.

"Tell me," I said, "if I take Delora's place to-night, and if your scheme is successful, does that free him? Will he be able to come back? Will it be for the benefit of mademoiselle?"

"But most certainly!" Louis answered earnestly. "It is not an organization against which we fight. It is one or two desperate men who believe themselves robbed. Once they are out of the way, Delora can walk the streets a free man. There would be nothing," he added, "to prevent your seeking his friendship or the friendship of his niece."

"Very well," I agreed. "I will spend the night in Mr. Delora's rooms. I shall leave it to you to make all the arrangements."

Louis looked at me with a curious expression in his face.

"You understand, monsieur," he said slowly, "that there may be danger?"

"Naturally I understand," I said. "If it comes to a fight, I shall be prepared, and I have had a little experience."

"However well armed you may be," Louis said, "there will be a risk.

Our enemies are swift and silent. One of them, at any rate, is an accomplished criminal. They are too clever for us unaided. I could take Mademoiselle Delora to Scotland Yard to-day, and I could tell them what we fear. They might patrol the hotel with the police, and even then you would wake in the night and find some one by your bedside."

"By the bye, Louis," I said, "why all this mystery? According to you, Delora is an honest man. Why don't you go to the police?"

Louis shook his head.

"We are not free to do that," he said. "Delora is honest, but it is a great secret which he controls, and the only chance of using it successfully is to keep it a secret from the whole world!"

"How am I to be introduced into the room, Louis?" I asked.

"That," he answered, "will be easy. There are two lifts, as you know,--one from the smoking-room and one from the entrance hall. The number of Mr. Delora's apartment is 157. Here, by the bye, monsieur, is a key."

I took it and put it in my waistcoat pocket.

"You will ascend by the lift from the smoking-room to the top floor,"

Louis continued. "You can then descend by the other lift to the fifth floor, and walk boldly into the sitting-room. The door on the right will be Mr. Delora's bedroom, and of that there will be, after midnight, a key upon the mantelpiece in the sitting-room."

"But Miss Delora?" I asked. "What of her? The sitting-room connects, also, with her apartments."

"Mademoiselle will be told something of this during the evening,"