"What's the matter?" Kass asked. "You act as if you're glad to see us, but wished we hadn't come." "Why are you here?" she asked with a troubled frown. The Earthmen told her of what had transpired--that they were now condemned for life to serve in the dark hemisphere. As they spoke her fears seemed to vanish. She became radiant with delight. "Then you have come at the right time!" she cried. "Our slavery is at an end, and you shall pilot us back to the Mother planet!" "You're not crazy, are you kid?" Sine asked, lifting her little pointed chin with his hand. "No!" she laughed delightfully. "Not crazy!" And she would have embraced Sine again. "My father has been building a ship for the past two years, hoping to escape to Ganymede, or some other moon of Jupiter. But now we shall go to Earth!" She clapped her hands excitedly. "Listen! Let's get this straight," Lents demanded. "You say your dad has built a ship. Where is it?" "Way down in the bottom of the hemisphere. That's where all the Mugs are, working on it when they have time. Dad's chest feels better again." "They have built a ship, huh?" Sine was trying to suppress the hope that flamed up madly. "How'll they get it out?" "They've made an airlock, so that when we leave the escaping air won't give us away." It was one of these things that seem too good to be true. But when the Earthmen accompanied the girl to the secret workshop, directly next to the sphere's outer skin, they found she had spoken the truth in every respect. The men there, nearly all pathetic wrecks of the First Race's system, were at first a little doubtful about admitting the Earthmen, but one after another they were won over to the idea of seeking sanctuary on Earth rather than on some satellite of Jupiter where they would never be entirely safe. Besides, the Earthmen, though they had been stripped of all their weapons, represented additional fighting strength. They made their final preparations with mixed feelings. Many of the Mugs had relatives on Jupiter, though few had wives or children. Even women of the Second Race had no desire to share the fate of a man condemned to a lifetime in the black half of the Bubble. Those few women who had accompanied their men to the metal satellite would, of course, be taken along, for the escape ship was commodious. The next two weeks were filled with arduous labor, but at last the ship was ready, and observation through a small port which had been installed, showed that they were about to enter the shadow of Jupiter. Under cover of darkness they would leave the airlock. They would accelerate past The Bubble. Centrifugal force would send them away from Jupiter. At the same time their velocity with relation to the sun would be diminished. Lents plotted a long, graceful curve that would bring them to Earth with the best possible speed. Proserpina's father lay on the floor, peering out through the port.