room was empty. She had taken advantage of his momentary absorption to slip away. He stepped outside and stood by the lift, listening. The landing was deserted, and there was no sound of any one moving anywhere. The lift itself was on the ground floor. It had not ascended recently or he must have heard it. He returned to his room and softly closed the door. Again the sense of emptiness oppressed him. A faint perfume around the place where she had stood came to him like a whiff of some delicious memory. He set his teeth, lit a cigarette, and sitting down at his desk wrote a few lines to his neighbour, embodying the message which had been given him. With the note in his hand he ascended to the next floor. There was apparently no light in flat number 11, but he rang the bell and listened. There was no answer, no sound of any one moving within. For nearly ten minutes he waited—listening. He was strongly tempted to open the door with his own key and see for himself if she was there. Then he remembered that Barnes was a man whom he barely knew, and cordially disliked, and that if he should return unexpectedly, the situation would be a little difficult to explain. Reluctantly he descended to his own flat, and mixing himself a whisky and soda, lit a pipe and sat down, determined to wait until he heard Barnes return. In less than a quarter of an hour he was asleep! CHAPTER II THE HORROR OF THE HANSOM Wrayson sat up with a sudden and violent start. His pipe had fallen on to the floor, leaving a long trail of grey ash upon his waistcoat and trousers. The electric lights were still burning, but of the fire nothing remained but a pile of ashes. As soon as he could be said to be conscious of anything, he was conscious of two things. One was that he was shivering with cold, the other that he was afraid. Wrayson was by no means a coward. He had come once or twice in his life into close touch with dangerous happenings, and conducted himself with average pluck. He never attempted to conceal from himself, however, that these few minutes were minutes of breathless, unreasoning fear. His heart was thumping against his side, and the muscles at the back of his neck were almost numb as he slowly looked round the room. His eyes paused at the door. It was slightly open, to his nervous fancy it seemed to be shaking. His teeth chattered, he felt his forehead, and it was wet. He rose to his feet and listened. There was no sound anywhere, from above or below. He tried to remember what it was