This is the true story of Indian agent John Philip Clum (Audie Murphy) as told by Clum's son in the 1936 biography Apache Agent. The film begins in 1874, as Clum, an Eastern government representative, arrives in San Carlos, Arizona. He is sent to try a new approach to peace with Apaches based on respect for autonomy rather than submission to Army. He faces suspicions from the white settlers, the Army and the Indians, especially Geronimo.
An Indian widow, Tianay (Anne Bancroft) falls in love with Clum, despite the fact he is engaged to Mary Dennison (Pat Crowley). Clum is helped by his Irish American friend, Tom Sweeney (Charles Drake).