Sent to protect a U.S. outpost on the desolate frontier, Lt. John Dunbar finds himself alone in the vast wilderness. Befriending the very people he's sent to protect the outpost from, the Sioux Indians, Dunbar slowly comes to revere those he once feared. When the encroaching U.S. Army threatens to overrun the Sioux, he is forced to make a difficult choice.

Centers around three powerful men: Charles Eastman, a young, Dartmouth-educated Sioux doctor; Sitting Bull, the proud Lakota chief who refuses to submit to U.S. government policies; and Senator Henry Dawes, one of the men responsible for the government policy on Indian affairs.