The fugitives now aided each other simply to avoid murder. They gathered together exhaustedly at nightfall, and those who were strongest did what they could for the others. By day, those who could walk scattered to separate hiding places, so that if one were discovered, the others might still escape the indignity of being butchered. They had no stronger motive than that. They were merely trying to die with dignity, instead of being killed as sick beasts. Which bespoke a tradition and an attitude which Calhoun approved. People like these would know something of the science of probability in human conduct. Only they would call it ethics. But the strangers--the invaders--the occupiers of the city were of another type. They probably came from another world. "I don't like this," said Calhoun coldly. "Just a moment." He went over to Murgatroyd. Murgatroyd seemed to droop a little. Calhoun checked his breathing and listened to his heart. Murgatroyd submitted, saying only "_Chee_" when Calhoun put him down. "I'm going to help you to your rendezvous," said Calhoun abruptly. "Murgatroyd's got the plague now. I ... exposed him to it, and he's reacting fast. And I want to see the others of your group before nightfall." The girl just managed to get to her feet. Even speaking had tired her, but she gamely though wearily moved off at a slant to the hillside's slope. Calhoun picked up the odd weapon and examined it thoughtfully. He wound it up as it was obviously meant to be. He picked up the missile it had fired, and put it in place. He went after the girl, carrying it. Murgatroyd brought up the rear. Within a quarter of a mile the girl stopped and clung swaying to the trunk of a slender tree. It was plain that she had to rest, and dreaded getting off her feet because of the desperate effort needed to arise. "I'm going to carry you," said Calhoun firmly. "You tell me the way." He picked her up bodily and marched on. She was light. She was not a large girl, but she should have weighed more. Calhoun still carried the quaint ancient-type weapon without difficulty. Murgatroyd followed as Calhoun went up a small inclination on the greater hillside and down a very narrow ravine. Through brushwood he pushed until he came to a small open space where shelters had been made for a dozen or so human beings. They were utterly primitive--merely roofs of leafy branches over frameworks of sticks. But of course they were not intended for permanent use. They were meant only to protect plague-stricken folk while they waited to die.