But Christabel did not dally long in the drawing-room. As she went upstairs and along the corridor she heard the snapping of the electric lights all over the house as the servants were preparing to retire. She paused just a moment in the alcove where the precious Rembrandt was and located carefully the position of the switch there. Then she retired to her own room, where she changed her dress for a simple black gown. A big clock somewhere was striking twelve as she finished. She looked out of her door. The whole house was in darkness, the silence seemed to cling like a curtain. She paused for a moment as if afraid to take the next step. If it was fear, she shook it aside resolutely and crept into the corridor. She carried something shining in her hands--something that gleamed in the dim, uncertain light from the big window. She stood just for an instant with a feeling that somebody was climbing up the ivy outside the house. She felt her way along until she came to the alcove containing the Rembrandt and then she stopped. Her hand slid along the wall till her fingers touched the switch of the electric light. She stood for a long time there perfectly motionless. It was a still night outside, and there was nothing to account for the rustling of the ivy leaves. The rattling came in jerks, spasmodically, stopping every now and then and resuming again. It was no longer a matter of imagination, it was a certainty. Somebody was climbing up the ivy to the window. Leaning eagerly forward, Christabel could hear the sound of laboured breathing. She seemed to see the outline of an arm outside, she could catch the quick rattle of the sash, she could almost see a bent wire crooked through the beaded edges of the casement. Yes, she was right. The window swung noiselessly back and a figure stood poised on the ledge outside. With a quick breath and a fluttering of her heart Christabel felt for the switch. "It will be all right," she murmured; "the other one will fancy that the light is necessary. Courage, my dear courage, and the game is yours. Ah!" The intruder dropped inside and pulled the window behind him. Evidently he was on familiar ground, though he seemed to be seeking an unfamiliar object. Christabel's hand stole along to the switch; there was a click, and the alcove was bathed in brilliant light. The intruder shrank back with a startled cry. He rubbed his dazed eyes. "Why not come in through the front door, Mr. Littimer?" Christabel drawled, coolly. Frank Littimer had no words for a moment. He was wondering who this woman was and what she was doing here. American, evidently, by her accent, and also by the revolver that she handled so assuredly.