"You are positive the murderer could not have slipped by you all, as the door flew open, and so made his escape?" "That was utterly impossible. We were all grouped around the door and stayed so, until we entered the sitting room ourselves. There was nobody there but Aunt Ursula, herself----" "Dead?" "Yes, but only just dead. Polly heard her faint moans, after her loud screams, you know, before we broke in." "And what were the words she used when she screamed out?" "I don't know exactly, but they were cries for help, and I'm sure Polly said she called out 'Thieves!' Of course, she was unable to speak coherently." "Now," began Stone, "to look at this one point. Her assailant had to get out or stay in, didn't he? You're sure he didn't get out, therefore he must have stayed in. A man of flesh and blood cannot go through walls, like a ghost." "But he didn't stay in!" cried Iris. "We searched the room at once, there was nobody in it. You know there's almost no place to hide. We looked behind the window curtains, and all such places--and, too, we were in this room continuously, till others came, and no one could have gone through here without being seen." "Nor could he get out of the barred windows. Then what became of him?" "Ah, Mr. Stone," said Hughes, "that's the question that has puzzled us all. If you can solve that, we can begin to look for the murderer!" "Meantime, we must assume him to be a spook? Is that it?" Stone smiled a little at the complacent Hughes. "I don't say that, but I do call the manner of his exit an insoluble mystery." "If _he_ could accomplish it, _I_ can find out how," Stone said, quietly. He had no air of bravado, but he made the statement in all sincerity. "I believe you can!" declared Lucille. "That's why I wanted you, Mr. Stone. I've heard of your almost unbelievable cleverness, and I knew if anybody could get to the bottom of this mystery, you could." "I don't mind admitting that it is seemingly the most inexplicable one I ever encountered, but I shall do my best. And I want the coöperation of you all. There are many things to be told me yet; remember I've only just heard the main details, and each of you can give me light in different ways. I'll call on you for information when necessary. Also, Miss Darrel, will you extend your hospitality to my young assistant?" "That boy?" Lucille smiled. "Yes; Terence, his name is. He's my right-hand man and attends to a lot of detail work for me." "He's a handful," and Lucille laughed again. "I saw him in the kitchen, wheedling round Polly, and begging for cookies." "I'll warrant he got 'em," said Stone. "He has a way with him that is persuasive, indeed. But he won't make you any bother. Fix him up a bed in the loft, or anywhere. He's willing to rough it." "Oh, no, he can have a decent room, of course. I'll give him one in the garage, there's a nice one next to Campbell's." At that moment, Terence appeared at the door.