“The Plat du Jour,” he remarked, “is excellent.  Monsieur should try it.  After a few days of French cookery,” he continued, “a simple English dish is sometimes an agreeable relief.”

“Thank you, Louis,” I answered.  “Tell me what has become of Mr. Delora?”

My sudden attack was foiled with the consummate ease of a master—­if, indeed, the man was not genuine.

“Mr. Delora!” he repeated.  “Is he not staying here,—­he and his niece?  I have been looking for them to come into luncheon.”

“His niece is here,” I answered.  “Mr. Delora never arrived.”

Louis then did a thing which I have never seen him do before or afterwards,—­he dropped something which he was carrying!  It was only a wine carte, and he stooped and picked it up at once with a word of graceful apology.  But I noticed that when he once more stood erect, the exercise of stooping, so far from having brought any flush into his face, seemed to have driven from it every atom of color.

“You mean that Mr. Delora went elsewhere, Monsieur?” he asked.

I shook my head.

“They travelled up from Folkestone,” I said, “in my carriage.  At Charing Cross Mr. Delora, who had been suffering, he said, from sea-sickness, and who was certainly very nervous and ill at ease, jumped out before the train had altogether stopped and hurried off to get a hansom to come on here.  It had been arranged that I should bring his niece and follow him.  When we arrived he had not come.  He has not been here since.  I have just left his niece, and she assured me that she had no idea where he was.”

Louis stood quite still.

“It is a most singular occurrence,” he said.

“It is the strangest thing I have ever heard of in my life,” I answered.

“Monsieur is very much interested, doubtless,” Louis said thoughtfully.  “He travelled with them,—­he expressed, I believe, an admiration for the young lady.  Doubtless he is very much interested.”

“So much so, Louis,” I answered, “that I intend to do everything I can to solve the mystery of Delora’s disappearance.  I am an idle man, and it will amuse me.”

Louis shook his head.

“Ah!” he said, “it is not always safe to meddle in the affairs of other people!  There are wheels within wheels.  The disappearance of Mr. Delora may not be altogether so accidental as it seems.”

“You mean—­” I exclaimed hastily.

“But nothing, monsieur,” Louis answered, with a little shrug of the shoulders.  “I spoke quite generally.  A man disappears, and every one in the world immediately talks of foul play, of murder,—­of many such things.  But, after all, is that quite reasonable?  Most often the man who disappears, disappears of his own accord,—­disappears either from fear of things that may happen to him, or because he himself has some purpose to serve.”

“You mean to suggest, then, Louis,” I said, “that the disappearance of Mr. Delora is a voluntary one?”