The _maître d'hôtel_ passed on, well satisfied that he had interested the three distinguished looking gentlemen who dined alone. Wrayson, as soon as he was out of hearing, leaned over the table. "It is on that night," he said to Duncan, "that I come into touch with the affairs of which our friend has spoken. The man Barnes had a flat corresponding to mine on the floor above. I returned home about midnight and found a young lady, who was a complete stranger to me, engaged in searching my desk. I turned up the lights and demanded an explanation. She was apparently quite as much surprised to see me as I was to see her. It appeared that she had imagined herself in Barnes' flat. Whilst I was talking to her, the telephone bell rang. Some unknown person asked me to convey a message to Barnes. When I had finished she was gone. I sat down and tried to make head or tail of the affair. I couldn't. Barnes was a disreputable little bounder! This girl was a lady. What connexion could there be between the two? I fancied what might happen if she were surprised by Barnes, and I determined not to go to bed until I heard her come down. I fell asleep over my fire, and I woke with a start to find her once more upon the threshold of my room. She was fainting--almost on the point of collapse! I gave her some brandy and helped her downstairs. At the door of the flat was a cab, and in it was the man Barnes, dead--murdered!" The breath came through Duncan's teeth with a little hiss. One could fancy that he was wishing that his had been the hand to strike the blow. The Baron glanced round casually. He called a waiter and complained of the slow service, sent for another bottle of wine, and lit a cigarette. "I think," he said, "that we will pause for a moment or so. Mr. Wrayson's narrative is a little dramatic! Ah! Mademoiselle la danseuse goes! What a toilet!" Mademoiselle favoured their table with her particular regard as she passed out, and accepted with a delightful smile the fan which she dropped in passing, and which the Baron as speedily restored. He resumed his seat, stroking his grey moustache. "A very handsome young lady," he remarked. "I think that now we may continue." "The girl?" Duncan asked quickly. "Was your sister," Wrayson answered. There was a moment's intense silence. Duncan was doing his best to look unconcerned, but the hand which played with his wineglass shook. "How--was he murdered?" "Strangled with a fine cord," Wrayson answered. "In the cab?" "There or inside the building! It is impossible to say." "And no one was ever tried for the murder?" "No one," Wrayson answered. Duncan swallowed a glassful of wine. "But my sister," he said, "was in his rooms--she might have seen him!" "Your sister's name was never mentioned in the matter," Wrayson said. "I was the only witness who knew anything about her--and--I said nothing." Duncan drew a little breath. "Why?" he asked.