The Bat was working rapidly. She heard his quick, nervous movements; apparently he had come back for something and secured it, for now he moved again toward the door. But he was too late; they were returning that way. She heard him mutter something and quickly turn the key in the lock. Then he seemed to run toward the window, and for some reason to recoil from it. The next instant she realized that he was coming toward the mantel-room, that he intended to hide in it. There was no doubt in her mind as to his identity. It was the Bat, and in a moment more he would be shut in there with her. She tried to scream and could not, and the next instant, when the Bat leaped into concealment beside her, she was in a dead faint on the floor. Bailey meanwhile had crawled out on the roof and was carefully searching it. But other things were happening also. A disinterested observer could have seen very soon why the Bat had abandoned the window as a means of egress. Almost before the mantel had swung to behind the archcriminal, the top of a tall pruning ladder had appeared at the window and by its quivering showed that someone was climbing up, rung by rung. Unsuspiciously enough he came on, pausing at the top to flash a light into the room, and then cautiously swinging a leg over the sill. It was the Doctor. He gave a low whistle but there was no reply, save that, had he seen it, the mantel swung out an inch or two. Perhaps he was never so near death as at that moment but that instant of irresolution on his part saved him, for by coming into the room he had taken himself out of range. Even then he was very close to destruction, for after a brief pause and a second rather puzzled survey of the room, he started toward the mantel itself. Only the rattle of the doorknob stopped him, and a call from outside. “Dale!” called Bailey’s voice from the corridor. “Dale!” “Dale! Dale! The door’s locked!” cried Miss Cornelia. The Doctor hesitated. The call came again. “Dale! Dale!” and Bailey pounded on the door as if he meant to break it down. The Doctor made up his mind. “Wait a moment!” he called. He stepped to the door and unlocked it. Bailey hurled himself into the room, followed by Miss Cornelia with her candle. Lizzie stood in the doorway, timidly, ready to leap for safety at a moment’s notice. “Why did you lock that door?” said Bailey angrily, threatening the Doctor. “But I didn’t,” said the latter, truthfully enough. Bailey made a movement of irritation. Then a glance about the room informed him of the amazing, the incredible fact. Dale was not there! She had disappeared! “You—you,” he stammered at the Doctor. “Where’s Miss Ogden? What have you done with her?” The Doctor was equally baffled. “Done with her?” he said indignantly. “I don’t know what you’re talking about, I haven’t seen her!” “Then you didn’t lock that door?” Bailey menaced him. The Doctor’s denial was firm.