All hands set to work completing repairs on the main stern tubes, the only ones necessary to drive the _San Francisco_ forward. In less than three hours, Edwards pronounced the work done to his satisfaction. As the light began to creep in toward the base of the cliff, the huge ship rose slightly off the ground, the tubes glowed red and, guided by a powerful searchlight installed on the bow, Edwards pointed his craft toward the gleaming metal patch that marked the position of the pirate cave. At short range, Holden, Linet, and Erickson opened with the three _hexoxen_ guns. They saw the bursts take effect on the metal. Edwards turned the power on full, and they felt the floor leaping under them. Would the bow of the _San Francisco_ hold? Would they all be crushed to death at the impact? Another moment would tell. Holden saw the metal plates dead ahead, could distinguish the seams marking the air-lock. He fired one final shot, and flung himself to the floor of the pilot room, endeavoring to find some means of bracing himself for the shock. Then it came! Torn from his position, he saw the plates buckling and heaving about him. The lights went out. A great crash sounded in his ears, and everything went black. In a moment he regained consciousness, and staggered to his feet, bruised and dizzy. Thank God, his space suit had not been harmed! A faint glow from the outside made things visible and he saw that the shock had torn a huge piece out of the plating of the pilot room. A hand clutched his elbow, and through the phone in his space suit he heard Linet's voice. "Erickson and Edwards are knocked out. Let's see what we did to these chaps here." * * * * * Rushing back through the corridor, they collected as many of the crew as were able to move, flung open the heavy doors of the air-lock, and scrambled down to the floor of the cave. Here and there lay bodies, pirates caught unawares. Suddenly Holden saw a blue flash. One of the mechanics clutched at his breast and fell, dead in an instant. "Some of these fellows are still alive. They're using ray pistols," Holden shouted into his suit phone. Even as he spoke he heard the sound of running feet from the darkness in the rear of the cave, where the bow of the _Silver Death_ was barely visible in her cradle, and in a moment at least fifty figures, pirates who had somehow escaped the fatal cold of space, clad in clumsy suits and brandishing pistols, flung themselves desperately upon the smaller party. Blue flashes were everywhere as the battle commenced, but the only sound was of struggling feet, with an occasional thud as a body hit the floor. The pirates had been weakened by their long stay on the moon, and moved slowly, but the surprise of their attack, and the superiority of numbers had given them some advantage. It was man to man fighting, savage and merciless.