Gray Bear, young warrior of the Missouris, is sent to learn the identity of the raiders who looted his home village on the Missouri River. In the woods at night he is attacked by a mysterious being with too many arms and legs to be human. His brother, an apprentice shaman, appears and treats his wound. In a cave the brothers find a starving man whom they can use as guide. Gray Bear acquires a faithful follower, a big and very brave dog. Soon they are captured by warriors of a kindred people who take them as guests to the big town at the center of the world. The shaman conjures up a frightful vision by mass hypnosis and Gray Bear trains for war with fierce members of his age group. Threatened by a rival shaman, the brothers must flee from the town but not before Gray Bear wins the love of the beautiful daughter of his host. He defeats his assigned executioner, a supposedly invincible giant champion warrior. On the far western prairie Gray Bear meets a huge Grizzly bear and claims it as his totem. The shaman finds the village of the raiders and “sends his spirit” to steal back the sacred bundle of his people from a body on a burial scaffold He also steals a Bear Claw necklace for Gray Bear to wear. For this he is stricken with a mysterious sickness. In the homeward bound canoe he is near death but is restored to health by a mysterious incident in which the necklace is restored to its spirit owner. During a vigil, Gray Bear sees his faithful dog as a spirit wolf. He leads young men of the wolf clan in a successful attack against tribal enemies and becomes a war chief eligible to marry the princess of his dreams. The shaman entertains (terrifies) the members of his home village with mass hypnosis and becomes respected and honored by all.