Suppose that mammoths, sabertooth cats and other large ice-age animals had been transplanted to another planet long ago. Suppose further that the planet, Falaron, has developed an economy based primarily on guided tourism, including Challenge journeys recognized though much of the Confederation as adulthood trials.

Roi and his best friends from slavery are taking such a Challenge journey. They look forward to a vacation of dog sledding, hang gliding, horseback trekking, sailing, whitewater rafting and rock climbing—though friction is developing within the group. Their guide, Penny, finds the four a refreshing change from her usual spoiled clients, though she is worried by the unusual number of accidents.

What no one realizes is that Roi's older half-brother and rival, Zhaim, is plotting to take advantage of the trip to kill them—and he will stop at nothing to get Lai and Marna out of his way.