Richard Harris plays the early nineteenth-century English aristocrat John Morgan, who, with the intent of "finding himself" apart from his privileged heritage, embarks on an extended hunting expedition in North America. Morgan instead finds himself a Sioux prisoner (his captors call him "horse"). His only salvation lies in proving his manhood and, ultimately, his dedication to the tribe, in a series of grisly endurance tests and tortures. He marries Running Deer (Corinna Tsopei) and, when the Chief, Yellow Hand (Manu Tupou), is killed, takes over leadership of the tribe. "With authentic Indians providing the majority of his cast, and over eighty per cent of the dialogue in Sioux, Elliot Silverstein clearly intended his film as an accurate recreation of Indian conditions, practices, and attitudes in the early nineteenth century. This anthropological emphasis was presumably intended to underline the relative nature of morality; and the confrontation between pampered aristocrat and primitive tribe, with the transition from mutual contempt to mutual respect, (intended to provide the) device for conveying this message...." --Monthly Film Bulletin