They were all gone from the room now, but there was in it one thing of life that had been there before. It lay behind the inlaid screen which, standing on roller-legs, lay along the wall at one place. The Hawk did not look behind the screen. He could see under it, to know that no one lurked there. He knew what it was meant to conceal. There his promise lay. But his promise could not be fulfilled immediately. There were four wings to the building, four doors leading into the laboratory, and he had inspected but one. An open door to his right revealed a corridor similar to the one he had reconnoitered. He repeated down it his methodical search and found no one. Then he returned to the laboratory. Surely there were men somewhere! Surely someone was behind one of the two closed doors remaining! Gun and flashlight still at the ready, Carse listened a moment at the nearest one. Silence. He grasped the knob, turned it and quickly threw the door open. A rapid glance revealed no one. Wary and alert, he passed through, and discovered that in this wing were the personal living quarters of Dr. Ku Sui. The quarters were divided into five rooms: living room, bedroom, library, dining room and kitchen, and the huge metal figure passed through all five, the cold gray eyes taking in every detail of the comfortable but not luxurious furnishings. There was a great interest to him, but it would have to wait. He reentered the laboratory and went to the remaining door. Bending his head he again listened. A sound--a faint whisper? He fancied he heard something. Ready for whatever it was, Carse pulled the door wide. And before him he saw the control room of the asteroid, and the men for whom he had been hunting. * * * * * They were white men. Carse recognized them immediately as the four assistants of Dr. Ku Sui. Once, they had been eminent on Earth, respected doctors of medicine and brain surgery, leaders in their profession: now they were like the mechanicalized coolies. For their brains, too, the Eurasian had altered, divested of all humanity and individuality, so as to utilize unhampered their skill with medicine and scalpel. They were clad in soft yellow robes and seated at ease at one end of a room crowded with a bewildering profusion of gauges, machines, instruments, screens, wheels, levers, and other nameless controlling devices. They did not show surprise at the huge clumsy figure that stood suddenly before them, a raygun in one hand. Like the coolies, their clean-cut features did not change under emotion. All they did was rise silently, as one, gazing at the adventurer out of blank eyes, saying nothing, and making no other move. Carse tried simple measures in dealing with them. His voice gentle yet firm, he said: