The lights inside the ship dimmed and burned blue. There was a screeching whine that rose up and out of hearing, clawing at the nerves as it went, and then there was a moment of awful vertigo when the ship and everything in it seemed to slip and fall sideways in an insane fashion. The open ports slid shut automatically. Just before they closed Birrel caught a glimpse through them of the stars he had been looking at only a few moments before. They shifted, streamed like burning rain, and vanished, to be replaced by squiggling lines of lights. Then the ports were shut and there was nothing except the personal sense of disorientation to show that anything had happened. Complacently, like one who knows he is dreaming and that therefore these strange things are not really happening and so need not be taken seriously, Birrel listened to the voices of the men, speaking technical words of no meaning to him as they went through what was apparently a routine check. Then the radarman said, "They're right with us." Thile grunted. "Full acceleration," he said. "Build up as fast as you can. Maybe their generators aren't as good as ours." * * * * * The whining began again but on a different note. Birrel pictured himself inside an iron egg flying through space--what kind of space?--at double, triple, quadruple the speed of light. He erased the thought from his mind as quickly as he could. He said to Kara, "Why haven't people done more star-travelling? You obviously have a workable drive." "We haven't had the time until recently," Kara said. "The Irrians kept us too busy. Then the few exploratory trips we did make to neighboring systems were discouraging. In most cases the planets were uninhabitable, and the ones that did have life forms were pretty awful. Our government hasn't encouraged star flight. I think they're afraid of what might come flying back our way." The ship quivered and trembled. Birrel thought he could almost feel the atoms crawling in the metal under his hand. "Do you ever hit things?" he asked. "Like stars, I mean." "Not very often. But I believe the results are quite spectacular. You become a nova almost at once." He laughed. He did not ask any more questions. The whining levelled off at last, refusing to go any higher. A collection of needles steadied on the main control-board. Vray said, "That's it." The radarman shook his head and said, "They're still with us." The lines deepened in Thile's face, turning it grim and hard. "Action stations. We'll try and get them before they get us." Birrel said, "What do you want me to do?" "Back in your bunk and strap in. This is liable to be rough." He shook his head. "There must be something I can do." "You'd only be in the way," Kara said. She was already removing a protective panel from a control-board ominously marked in red. She smiled, to take the sting out of the words. "You'll need a vac-suit. Here, Rett's will fit you."