“You mean the Austrian murderer?”

Colonel Damery threw up his kid-gloved hands with a laugh. “There is no getting past you, Mr. Holmes! Wonderful! So you have already sized him up as a murderer?”

“It is my business to follow the details of Continental crime. Who could possibly have read what happened at Prague and have any doubts as to the man’s guilt! It was a purely technical legal point and the suspicious death of a witness that saved him! I am as sure that he killed his wife when the so-called ‘accident’ happened in the Splugen Pass as if I had seen him do it. I knew, also, that he had come to England and had a presentiment that sooner or later he would find me some work to do. Well, what has Baron Gruner been up to? I presume it is not this old tragedy which has come up again?”

“No, it is more serious than that. To revenge crime is important, but to prevent it is more so. It is a terrible thing, Mr. Holmes, to see a dreadful event, an atrocious situation, preparing itself before your eyes, to clearly understand whither it will lead and yet to be utterly unable to avert it. Can a human being be placed in a more trying position?”

“Perhaps not.”

“Then you will sympathize with the client in whose interests I am acting.”

“I did not understand that you were merely an intermediary. Who is the principal?”

“Mr. Holmes, I must beg you not to press that question. It is important that I should be able to assure him that his honoured name has been in no way dragged into the matter. His motives are, to the last degree, honourable and chivalrous, but he prefers to remain unknown. I need not say that your fees will be assured and that you will be given a perfectly free hand. Surely the actual name of your client is immaterial?”

“I am sorry,” said Holmes. “I am accustomed to have mystery at one end of my cases, but to have it at both ends is too confusing. I fear, Sir James, that I must decline to act.”

Our visitor was greatly disturbed. His large, sensitive face was darkened with emotion and disappointment.

“You hardly realize the effect of your own action, Mr. Holmes,” said he. “You place me in a most serious dilemma, for I am perfectly certain that you would be proud to take over the case if I could give you the facts, and yet a promise forbids me from revealing them all. May I, at least, lay all that I can before you?”

“By all means, so long as it is understood that I commit myself to nothing.”

“That is understood. In the first place, you have no doubt heard of General de Merville?”

“De Merville of Khyber fame? Yes, I have heard of him.”

“He has a daughter, Violet de Merville, young, rich, beautiful, accomplished, a wonder-woman in every way. It is this daughter, this lovely, innocent girl, whom we are endeavouring to save from the clutches of a fiend.”

“Baron Gruner has some hold over her, then?”

“The strongest of all holds where a woman is concerned - the hold of love. The fellow is, as you may have heard, extraordinarily handsome, with a most fascinating manner, a gentle voice, and that air of romance and mystery which means so much to a woman. He is said to have the whole sex at his mercy and to have made ample use of the fact.”

“But how came such a man to meet a lady of the standing of Miss Violet de Merville?”