"Here we are," he said--"everything run by electricity. I thought that power house of Farrington's had a pretty stiff job, and now I see how heavy is the load which it has to carry. Step carefully into this," he continued, "and make a careful note of the way we are going. I think we must be about a hundred feet below the level of the earth; just gauge it roughly as we go up. Here we go." He pressed a button and up went the lift. They passed out of the little mine chamber, carefully propping back the swing door, and made their way along the corridor. "This looks like an apartment," said T. B., as he stopped before a red-painted steel door in one of the walls. He pressed it gently, but it did not yield. He made a further examination, but there was no keyhole visible. "This is either worked by a hidden spring or it does not work at all," he said in a low voice. "If it is a spring," said Ela, "I will find it." His sensitive hands went up and down the surface of the door and presently they stopped. "There is something which is little larger than a pin hole," he said. He took from his pocket a general utility knife and slipped out a thin steel needle. "Pipe cleaners may be very useful," he said, and pressed the long slender bodkin into the aperture. Instantly, and without sound, the door opened. T. B. was the first to go in, revolver in hand. He found himself in a room which, even if it were a prison, was a well-disguised prison. The walls were hung with costly tapestry, the carpet under foot was thick and velvety and the furniture which garnished the room was of a most costly and luxurious description. "Lady Constance!" gasped T. B. in surprise. A woman who was sitting in a chair near the reading lamp rose quickly and turned her startled gaze to the detective. "Mr. Smith," she said, and ran towards him. "Oh, thank God you have come!" She grasped him by his two arms; she was half hysterical in that moment of her release, and was babbling an incoherent string of words; a description of her capture--her fear--her gratitude--all in an inextricably confused rush of half completed phrases. "Sit down, Lady Constance," said T. B. gently; "collect yourself and try to remember--have you seen Poltavo?" "Poltavo?" she said, startled into coherence. "No, is he here?" "He is somewhere here," said T. B. "I am seeking for him now. Will you stay here or will you come with us?" "I would rather come with you," she said with a shiver. They passed through the door together. "Do all these doors open upon rooms similar to this?" asked T. B. "I believe there are a number of underground cells," she answered in a whisper, "but the principal one is that which is near." She pointed to a red-painted door some twenty paces away from the one from which they were emerging. There was another pause whilst Ela repeated his examination of the door.