In the wake of the Civil War, American settlers flood into the Great Plains, seizing Native American land as they go; but the Lakota leader, Sitting Bull, alongside Crazy Horse, organizes an unprecedented resistance movement.

Sitting Bull and Crazy Horse face George Armstrong Custer and the Seventh Cavalry in the battle of Little Bighorn; when their triumph over the U.S. Army fails to end the war they must continue the fight to preserve the Lakota way of life.