“If you will take the trouble to convince me, Louis,—­” I said.

Louis interrupted me; it was unlike him.  His little gesture showed that he was very nearly angry.

“Monsieur,” he said, “sometimes you fail to realize that at a word from us the hand of the gendarme is upon your shoulder.  We would make use of your aid gladly, but it must be on our terms—­not yours.”

“State them, Louis,” I said.

“We will tell you the truth,” Louis answered slowly.  “You shall understand the whole business.  You shall understand why Delora is forced to lie hidden here in London, what it is that he is aiming at.  When you know everything, you can be an ally if you will.  On the other hand, if you disapprove, you swear upon your honor as a gentleman—­an English gentleman—­that no word of the knowledge which you have gained shall pass your lips!”

“Louis,” I said, “I will have my lunch and think about this.”

Louis departed with his customary smile and bow.  I ordered something cold from the sideboard within sight, and a bottle of wine which was opened before me.  There scarcely remained any doubt in my mind now but that some part of Delora’s business, at any rate, in this country, was criminal.  Louis’ manner, his emphatic stipulation, made it a matter of certainty.  Again I found myself confronted by the torturing thought that if this were so Felicia could scarcely be altogether innocent.  Once when Louis passed me I stopped him.

“Louis,” I said, “let me ask you this.  Presuming things remain as they are, and I act independently, do you intend to prevent my seeing Miss Delora?”

“It is nothing to do with me,” Louis lied.  “It is the wish of her uncle.”

“Thank you!” I answered.  “I wanted to know.”

I finished my luncheon.  Louis saw me preparing to depart and came up to me.  My table was set in a somewhat obscure corner, and we were practically alone.

“I will ask you a question, Louis,” I said.  “There is no reason why you should not answer it.  There are laws from a legal point of view, and laws from a moral point.  From the former, I realize that I am, at this moment, a criminal—­possibly, as you say, in your power.  Let that pass.  What I want you to tell me is this,—­the undertaking in which Mr. Delora is now engaged, is it from a legal point of view a criminal one, or is it merely a matter needing secrecy from other reasons?”

Louis stood thoughtfully silent for some few moments.

“Monsieur,” he said at last, “I will not hide the truth from you.  According to the law in this country Mr. Delora is engaged in a conspiracy.”

“Political?” I asked.

“No!” Louis answered.  “A conspiracy which is to make him and all others who are concerned in it wealthy for life.”

“But the Deloras are already rich,” I remarked.

“Our friend,” Louis said, “has speculated.  He has lost large sums.  Besides, he loves adventures.  What shall you answer, Captain Rotherby?”