Joe Bass (Burt Lancaster), an American fur trapper, is making his way back home with a full cargo of hides when he encounters a group of Kiowa Native Americans in the United States led by Two Crows (Armando Silvestre), who insist on taking his furs. As "payment" they offer him a slave, Joseph Lee (Ossie Davis), whom they had previously taken from a group of Comanches. Reluctantly, realising he cannot fight them, Bass agrees to the trade.