"They have a reason," Prentiss said. "They're doing the same thing we're doing: fighting for survival."

Lake's pale brows lifted in question.

"The prowlers are the rulers of Ragnarok," Prentiss said. "They fought their way up here, as men did on Earth, until they're master of every creature on their world. Even of the unicorns and swamp crawlers. But now we've come and they're intelligent enough to know that we're accustomed to being the dominant species, ourselves.

"There can't be two dominant species on the same p. 34 world—and they know it. Men or prowlers—in the end one is going to have to go down before the other."

"I suppose you're right," Lake said. He looked at the guards, a fourth of them already reduced to bows and arrows that they had not yet had time to learn how to use. "If we win the battle for supremacy it will be a long fight, maybe over a period of centuries. And if the prowlers win—it may all be over within a year or two."

The giant blue star that was the other component of Ragnarok's binary grew swiftly in size as it preceded the yellow sun farther each morning. When summer came the blue star would be a sun as hot as the yellow sun and Ragnarok would be between them. The yellow sun would burn the land by day and the blue sun would sear it by the night that would not be night. Then would come the brief fall, followed by the long, frozen winter when the yellow sun would shine pale and cold, far to the south, and the blue sun would be a star again, two hundred and fifty million miles away and invisible behind the cold yellow sun.

The Hell Fever lessened with the completion of the shelters but it still killed each day. Chiara and his helpers worked with unfaltering determination to find a cure for