Sixteen-year-old Billy Parham is obsessed with trapping a renegade wolf that has raided his father's cattle ranch. By the time he finally succeeds, Billy has formed a close bond with the wolf and he decides to return the creature to its home. Months later, Billy returns to find that his parents have been murdered by horse thieves. He abducts his kid brother from a foster home, and they ride into Mexico to retrieve their property, encountering various characters on the way...