Desert guide Buckskin Hamilton learns that his brother Billy has been killed, supposedly by Jane Washburn in self-defense. As he leads a long wagon train, Buckskin suspects that Jane's gambling brother Donald, and his confederate, Guy Merton, are responsible. When the entire train is put on short allowance in the desert, Buckskin shows tenderness for the helpless, and wins the admiration of Jane, who confesses that Billy did not annoy her. Buckskin forces Donald and Merton to walk in the desert until heat and thirst cause the crazed men to believe that Donald killed Billy. When an Indian is killed by an emigrant, the band of Indians demand a life for a life, and Buckskin selects Donald. Donald tries to escape and is killed by the Indians. The wagon train reaches its destination. Jane, who has grown to love Buckskin, tries to stop him from continuing the trail, but he carries out his duty, telling her that he may return someday.