Again he pondered, his brow slightly contracted. “Where did Miss Hagerston sleep that night?” he asked suddenly. This was a question Cora had not expected. She colored violently. Then she said awkwardly: “Oh, at her flat in Knightsbridge, I suppose.” “You don’t know for certain?” “No. How should I?” “You say that you and Miss Hagerston are great friends, Mrs. Hartsilver, so I thought that probably you would know. She did not, I suppose, spend the night on Preston’s house-boat?” “How could she, Doctor Johnson, alone with him!” The doctor looked at her keenly, but she would not meet his gaze. “Why not be frank with me, Mrs. Hartsilver,” he said, lowering his voice. “She did spend the night on the boat with him, and you know it.” Cora looked terribly alarmed. “Oh, for heaven’s sake, doctor,” she exclaimed, “don’t let anybody know! Think what would be said, the inference that would be drawn, especially as they are engaged. I will be frank with you, then. I was with friends at Henley, and Yootha was to have met me at ten o’clock at night, and we were to have returned to town together. But she did not meet me, and I, thinking she must have gone back to London alone, returned with my friends. As soon as I got home I rang up her flat, and her maid said she had not come in; the maid was sitting up, awaiting her. I was dreadfully upset, and blamed myself for having missed her. “Next morning, about noon, she came to my house, looking very ill and worried. She said that she and Captain Preston had forgotten all about the time until it was too late to meet me, also by then the last train had gone. Captain Preston tried everywhere to find a bed for her, but there was not one to be had. Finally there was nothing for it but for her to return with the captain to his house-boat, where he gave her his bed and slept himself in his servant’s bed, while his servant slept outside in a deck-chair. That is what she told me, and I believe every word, because she couldn’t lie to me. There was no harm in it at all, believe me, there was not, but of course it would not do for people to know. Nobody knows but you and Captain Preston’s servant, a man absolutely to be trusted not to talk.” “And Miss Hagerston’s maid. At least she knows that her mistress did not come home.” Johnson began to pace the room. “Of course I shall treat what you have just told me as strictly confidential,” he said, “but the fact remains that we don’t know what happened during the time Preston and Miss Hagerston left Mrs. Mervyn-Robertson’s house-boat, and the time, late at night, when they returned to his own house-boat.” “What do you imply?” Cora asked sharply, drawing herself up.