He realized then what had happened. His steel frame had taken the full stock of Zuldi's voltage gun. And that shock had burned off the wire that had been shorting his energy at the back of his neck! He was standing there on his own two feet! He was moving his head! He was free! Withering blasts from a half dozen voltage guns tore suddenly into his steel body, rocking him on his feet. But he didn't care. He was free! A savage cry came from his steel throat as he brushed aside the creatures and their guns. He went directly to the opening in the floor, put his heavy foot against the trap door and kicked it shut with a splintering crash that wedged it tightly home. Then he turned slowly about to face Zuldi and the creatures. There was no escape for them now! From outside, came the sound of successive, powerful blasts. The black ship was bringing its heavy guns into action, was bombarding the city. Zurk caught two of the creatures as a great cat would catch mice. Their gibbering death-cries filled his ears with pleasure as he smashed their heads together and flung their lifeless bodies against the wall. "The disintegrator!" he shouted to Bob. "Knock that ship out of the sky! This will be a fight they will remember!" His steel fist crashed into the evil brain of another. Then came a roaring bolt of destruction more powerful than all the others. It struck the corner of the attic, quaked the building to its foundations and sent one wall of the laboratory swirling away in a burst of flying debris. Two of the trapped creatures sprang out of the opening, screaming. Zuldi would have followed had not Zurk clutched him up in his huge hands. Slowly, the man of steel twisted the evil creature's head about in a complete circle. Then he raised the lifeless body high into the air and cast it down into the dust of the street below. [Illustration: _His great steel hand shot out and seized Zuldi's scaly neck._] He turned to find Marene and Bob standing beside the gun. Marene was sobbing quietly. Bob was staring bewilderedly at the dangling end of one of the electrodes he held in his hands. "The blast from the ship!" he cried. "The blast from the ship carried away one of the electrodes! We are without power for the disintegrator!" Zurk took the severed cable into his own hands. He saw immediately that repairs were out of the question. A long section had been blasted away between the floor and the gun. And the disintegrator was useless without power! Another blast from the black ship shuddered the laboratory and brought answering sparks from Zurk's steel shell. Then he knew! The solution came startlingly clear to his brain. He would make the connection with his own metal body! * * * * * Grasping the cable tighter in his hand, he set his foot down heavily upon the other end that lay upon the floor.