Fourteen-year-old Clay and his older brother Mike are off on a trip they'll never forget. The excitement of traveling across the Southwest in Mike's old pick-up truck is made even better by Clay's dream of finding his favorite uncle, an ex-rodeo star who was last heard from somewhere in the vast and colorful land called Monumnet Valley.

But Mike soon gives up and heads for home, and Clay is even more determined to go on. With a job in a remote Navajo trading post and only a burro for transportion, he follows a lead on his uncle's whereabouts that takes him deep into the canyons of Navajo country, where he learns the ways of the tribe, the dangers of the wilderness, and discovers, just in time, the secret of what became of his long lost uncle.