Zurk could have told him. The answer was somewhere back in his sub-conscious mind. Zuldi had considered the metal giant as being but some Earthian god, a powerless entity. He had spat upon the god contemptuously and had left it standing. Marene's hand was upon the young man's arm and she was looking up into his eyes. "Bob," she said earnestly, "your gun _must_ be a success! It is not just for our own sakes; there are a thousand other lives depending upon it." Bob put his hand over hers. "It _will_ be a success!" he promised. Then, "But we've got to hurry. If they come a day earlier.... If they should happen to come tomorrow...." He left the sentence unfinished, gave Marene's hand a reassuring squeeze and hurried to the trap door that led down from the attic laboratory. Guyard was shocked to find that the two weeks was nearly up, was surprised to learn that his struggles against the thing at the back of his neck had sent him into such long periods of blackness. But the passing of time made one thing clear to him: it explained why he now constantly thought of himself not as Guyard, the man, but as Zurk, the giant of steel! The bustle of work in the laboratory made Zurk almost forget his helplessness. Time and time again, the young man hurried into the room to take molded pieces of steel from beneath his coat and to pile them upon the table before Marene. "Now!" he said finally. "Now if we can get them assembled in time!" He took off his coat and set to work with the hopeful energy of youth. "It's one of the blast rockets from the spaceship that brought us here," he explained. "The rockets get their power by disintegrating the atoms of fuel within their chambers. If we can change the procedure a bit, if we can get the disintegrating principle to work at long range instead of being confined merely to the fuel chamber." Zurk got the idea instantly. A disintegrator! The youth was constructing a long-range disintegrator with which to blow the black ship out of the sky! The thrill of it coursed through his brain. The Earthians were going to fight! They were going to make a last stand against the Creatures of Darkness. But he, Zurk, would be powerless to help. * * * * * Through the long hours of the day and night, Zurk sat there watching the two youngsters at their toil. They were working against time now, struggling for the right of freedom and happiness. But Zuldi might come. He might come before the gun was finished. Or he might come before the arrival of the black ship. Hours later, Bob made the final adjustments on the machine and stepped back to look at it. His face was pale and his hands trembled slightly with excitement. "Now to test it!" he told Marene. "And ... and I hope it works!" He turned the long snout of the gun toward the open window, connected the electrodes and made final adjustments.