The _Star Queen_ came out of overdrive. Her skipper arranged it to be done at the time when the largest possible number of her passengers and crew would be asleep. Those who were awake, of course, felt the peculiar inaudible sensation which one subjectively translated into sound. They felt the momentary giddiness which--having no natural parallel--feels like the sensation of treading on a stair-step that isn't there, combined with a twisting sensation so it is like a spiral fall. The passengers who were awake were mostly in the bars, and the bartenders explained that the ship had shifted overdrive generators and there was nothing to it. Those who were asleep started awake, but there was nothing in their surroundings to cause alarm. Some blinked in the darkness of their cabins and perhaps turned on the cabin lights, but everything seemed normal. They turned off the lights again. Some babies cried and had to be soothed. But there was nothing except wakening to alarm anybody. Babies went back to sleep and mothers returned to their beds and--such awakenings being customary--went back to sleep also. It was natural enough. There were vague and commonplace noises, together making an indefinite hum. Fans circulated the ship's purified and reinvigorated air. Service motors turned in remote parts of the hull. Cooks and bakers moved about in the kitchens. Nobody could tell by any physical sensation that the _Star Queen_ was not in overdrive, except in the control room. There the stars could be seen. They were unthinkably remote. The ship was light-years from any place where humans lived. She did not drive. Her skipper had a family on Cassim. He would not land a plague ship which might destroy them. The executive officer had a small son. If his return meant that small son's death as well as his own, he would not return. All through the ship, the officers who had to know the situation recognized that if chlorophage had gotten into the _Star Queen_, the ship must not land anywhere. Nobody could survive. Nobody must attempt it. So the huge liner hung in the emptiness between the stars, waiting until it could be known definitely that chlorophage was aboard or that with absolute certainty it was absent. The question was up to Doctor Nordenfeld. He had isolated himself with Kathy in the ship's hospital compartment. Since the ship was built it had been used once by a grown man who developed mumps, and once by an adolescent boy who developed a raging fever which antibiotics stopped. Health measures for space travel were strict. The hospital compartment had only been used those two times. * * * * *