"Was the door that opens from the dressing-room into the boudoir locked, or otherwise?" asked Ella. "To my certain knowledge it was locked till past ten o'clock: and I will tell you how I happen to know it," replied Mrs. Carlyon. "Some time after the exhibition of Mr. Conroy's sketches I went into the boudoir and found it empty of everybody except Philip Cleeve; he was lying on the sofa with one of his bad headaches. Thinking that my salts might be of service to him, I came into the dressing-room to get them. I have a clear recollection of finding the door between the two rooms locked then. I unlocked it, and having found the salts, I went back and gave them to Philip; but whether I relocked the door after me is more than I can say. Probably I did not. After a few words to Philip I left him, still lying on the sofa, and did not go near the boudoir again." A pause ensued. It seemed as if there was nothing more to be said. Not the slightest shadow of suspicion could rest on Philip Cleeve; the idea was preposterous. Both the ladies had known him since he was a boy, and his mother, Lady Cleeve, was one of Mrs. Carlyon's oldest friends. And, that suspicion could attach itself to any of the guests, was equally out of the question. Still, the one strange fact remained, that the casket could not be found. "We had better go to bed, I think," said Mrs. Carlyon at last, in a fretful voice. "If we sit up all night the case won't come back to us of its own accord." "I am ready to say with Higson that I shan't get a wink of sleep," remarked Ella, as she rose to obey. "One thing seems quite certain, Aunt Gertrude--that there must be a thief somewhere." CHAPTER III. CAPTAIN LENNOX STARTLED. There were other people beside Mrs. Carlyon who had cause to remember the night of Ella Winter's birthday party. As already stated, Captain Lennox and Mr. Bootle left the house together. They were walking along, arm-in-arm, smoking their cigars, when whom should they run against but Philip Cleeve, who had bid them goodnight half an hour before. "Why, Phil, my boy, what are you doing here?" cried Mr. Bootle. "I thought you were off to roost long ago." "I am taking a quiet stroll before turning in," answered Philip. "I thought the cool night air would do my head good, and I'm happy to say it has." "Then you can't do better than come along to my hotel with Mr. Bootle," said Lennox. "Let us have one last bottle of champagne together." Freddy seconded the proposition; and Philip, who seldom wanted much persuasion where pleasure was concerned, yielded after a minute's hesitation. He had come up to London for a few days' holiday, and there was no reason why he should not enjoy himself.