The walls of the cantonment hove suddenly in view through the murky atmosphere. The giants paused before a massive entrance like the gate of a feudal castle. Gavin climbed out of the litter and started to help Nadia down. Somewhere off in the distance he heard a faint popping. "What is it?" cried the girl, struck by his strained air of attention. "It sounds like the dum-dum fire. Listen!" They both fell silent. From the direction of the Nova came faintly a sound like a string of fire-crackers going off together. "It is dum-dum fire!" "But it can't be! It's impossible." The sound of explosions drifted to them again. Gavin sprang back into the litter. "Wait here," he cried. "Something's wrong at the ship." He knew that it couldn't be the Terran patrol spacers attacking. The balloon hadn't time to rise into the stratosphere yet. A great fear for the Nova's safety gripped him. Whatever the cost, the ship must be preserved intact so that Terra's scientists could examine her space drive. It had become the paramount issue, over-shadowing in importance even the detestable slave trade. "No!" Nadia cried. "Don't go back there." She flung herself on him, pressing her body flat against his. "Please, for my sake, Gavin!" He pushed her rudely aside. Just then the chief astrogator burst upon them, running from inside the cantonment. His strides were labored, his breath wheezing in his chest. He saw Gavin and shouted: "The ship's being attacked! They've radioed the cantonment for help!" "Who by?" "X's men!" The chief astrogator began to run down the paved highway toward the Nova and was swallowed by the fog. Gavin heard something whine through the air. He flung himself flat on his face, shouting at Nadia, "Down! They're shelling the cantonment!" The shell burst out of sight in the fog. A blast of air hit him like a wall of water. Nadia sat up, her face smudged where she'd groveled in the dirt. She was cursing like a spaceman. Gavin yanked her to her feet. "Clear out!" He began to haul her away from the doomed cantonment. Another shell lobbed over their heads to explode directly behind them. Gavin's hands were torn from the girl. He was blown a dozen feet by the blast. He lay where he lit, knowing nothing, feeling nothing. VIII Gavin's first impression was one of numbing cold. He opened his eyes. Pitch blackness engulfed him. He had difficulty orienting himself. Rather hazily, he recalled the shelling of the cantonment by X's men. Gradually his mind cleared. The swift Jovian night had fallen, he perceived, and the temperature had dropped sharply. Only his insulating outer garments had saved him from freezing. He began to grope around for Nadia's body. He found nothing but bare ground, stones, shrubs.