A prehistoric tale of the Pleistocene...
Banished from the Plains tribe of the Seven Rivers after offending the chief, Bru--a hunter--stalks into the saber-tooth haunted hills with only his stone knife and the furs on his back.
Bru is determined to find some way to appease the chief so he might return to the tribe. For if he doesn't return soon, the girl he loves will be mated to a hated rival.
Yet Bru's plans are thrown out of kilter when he runs afoul of a visitor from another world in need of a strong back . . . and an even stronger mind.
Bizarrely instructed in science and physics beyond the ken of his simple people, savage Bru soon finds himself forced to labor for a cruel master.