Shelton was crying out in pain and Lina sprang to her feet. "You beast!" she shouted at Cadorna. "Let him go." Then she was across the room, tearing at the unyielding metal bands that pinioned her father and slowly crushed him. Cadorna laughed mirthlessly. "Tell him to give me the dope," he retorted. "Then I'll let him go--for a while." Shelton's head hung on his chest, rolling weakly from side to side. Eddie doubted whether he could speak if he wished to. The Chilean was working at the controls, increasing the tension of those terrible tentacles. Eddie raised himself to his knees, watching Cadorna narrowly. He fingered the knife Lina had used in freeing him. No, he couldn't use that. The Chilean would cry out and queer everything. He laid it on the floor, within easy reach. Cadorna was cursing now, first Shelton and then the girl. His rage was maniacal. "Another notch!" he bellowed. Eddie rose silently and clamped his fingers on the Chilean's windpipe. Lina's eyes widened as she saw. She did everything in her power to keep Cadorna's attention occupied as Eddie sunk those fingers into Carlos' throat. The Chilean's eyes popped from his head as he struggled furiously to tear away the steel-sinewed hand that had stopped off his breath. Death was staring him in the face, and he could not cry out. His strength left suddenly as the fingers dug in deeper, and Eddie shook him as he would a rat. In a surprisingly short time he had slumped to the floor, and not until his squirmings ceased did Eddie loose that awful grip. "Another notch, you spiggoty!" * * * * * Eddie bent over the controls. Lina's pleadings mingled with the curses of Cadorna. She was cajoling now--telling the brute she'd go with him gladly if only he'd free her father; promising anything, everything, in the desperate attempt to keep him from discovering that his last henchman was out of the picture. But her words served only to spur Eddie to swifter action. He twirled the knobs of the dual control. The second robot was fading from view. He'd give Cadorna a dose of the thing he really feared. He eased off a little on the other control, releasing the pressure on poor Shelton's ribs as much as he dared. The position indicator of the second robot moved slightly as Eddie started the invisible monster toward the yelling gangster. He watched the screen closely. It was quite a trick, at that, controlling these things you couldn't see. All you had to go by were these sketchy representations in the teleview; tiny flecks of light that outlined the various movable members of the robot. "Eddie!" Lina screamed suddenly. "Look out!" But he had seen Cadorna wheel around as he watched his image on the screen. At that moment a tentacle was writhing its way around his thick neck. A bullet whistled past Eddie's ear and buried itself harmlessly in the wall.