The next year they trapped two unicorns, to begin the job of adapting and taming future generations of them. If they succeeded they would have utilized the resources of Ragnarok to the limit⁠—except for what should be their most valuable ally with which to fight the Gerns: the prowlers.

For twenty years prowlers had observed a truce wherein they would not go hunting for men if men would stay away from their routes of travel. But it was a truce only and there was no indication that it could ever evolve into friendship.

Three times in the past, half-grown prowlers had been captured and caged in the hope of taming them. Each time they had paced their cages, looking longingly into the distance, refusing to eat and defiant until they died.

To prowlers, as to some men, freedom was more precious than life. And each time a prowler had been captured the free ones had retaliated with a resurgence of savage attacks.

There seemed no way that men and prowlers could ever meet on common ground. They were alien to one another, separated by the gulf of an origin on worlds two hundred and fifty light-years apart. Their only common heritage was the will of each to battle.

But in the spring of one hundred and sixty-one, for a little while one day, the gulf was bridged.

Schroeder was returning from a trip he had taken alone to the east, coming down the long canyon that led from the high face of the plateau to the country near the caves. He hurried, glancing back at the black clouds that had gathered so quickly on the mountain behind him. Thunder rumbled from within them, an almost continuous roll of it as the clouds poured down their deluge of water.

A cloudburst was coming and the sheer-walled canyon down which he hurried had suddenly become a death trap, its sunlit quiet soon to be transformed into roaring destruction. There was only one place along its nine-mile length where he might climb out and the time was already short in which to reach it.