A English lord kidnapped by Indians becomes a part of their tribe.

Lord John Morgan, an aristocratic Englishman, is on a hunting expedition in the Dakotas in the early 19th century. The Sioux attack his camp and scalp his companions, but marvelling at Morgan's blonde hair, they capture him and drag him to their camp, where Chief Yellow Hand gives him to an old squaw, Buffalo Cow Head. When he is not being tortured or ridiculed, he serves as a beast of burden for the squaw. Warned by Frenchman Batise, who is also a slave to the Sioux, not to try to escape, Morgan decides to raise his status by learning the Sioux's speech and customs; later, by killing two scouts of a Shoshone war party, he proves himself to the tribe. Morgan and Running Deer, the daughter of Chief Yellow Hand, fall in love, despite Buffalo Cow Head's objections, and wish to marry; Morgan, however, must first endure the torture of the Sun Vow in which he is hung high above the ground by the skin of his chest. After performing this ritual, he and Running Deer are married. Yellow Hand is killed in a Shoshone attack, during which Morgan leads the defense of the Sioux and kills a Shoshone chief. Running Deer, who is pregnant, also dies as a result of wounds from the attack. After agreeing to become Buffalo Cow Head's son to prevent her from becoming an outcast, Morgan is named tribal chief for his bravery, but when the old woman dies, he leaves the Sioux and sadly returns to England.