The fictional Civil War officer who once saved Custer's life, Clayton leaves a journal describing his later career on the western frontier. As a civilian scout for the U.S. Army, he tries to head off the Fetterman Massacre. He is captured by Crazy Horse and taken into the Oglala Sioux tribe. For nine years he lives as an Indian -- the adopted son of Crazy Horse, an intimate of Sitting Bull, and the husband of a medicine woman. He rides with the Indians against the white invaders, but by 1876 he has to make a choice about who he really is.