Joe Bass, an American fur trapper, is on his way to sell the hides he has amassed over the winter. He encounters a group of Kiowa Indians led by Two Crows, who take his furs. In exchange, they give a disgusted Bass a slave, Joseph Lee, whom they had previously taken from a group of Comanches. Lee is a well-educated and refined house slave, unfamiliar with the ways of the wilderness. Bass sets out to recover the furs from the Kiowa. Lee makes an unsuccessful attempt to escape, then follows along. As Lee and Bass catch up to the Kiowa, they watch them being ambushed by a group of scalphunters, after the bounty offered by the government for each Native American scalp they bring in. The scalphunters, led by Jim Howie, kill the Kiowas and take Bass's furs. Bass and Lee trail the new group. Lee stumbles over a cliff and is captured by the scalphunters. Howie decides to sell him in Galveston, Texas. As they travel southwards, Jim Howie's girlfriend, Kate, reveals to Lee that they are heading for Mexico. He begins to win her favor, by doing her hair and telling her fortune, hoping she will persuade Howie to take him with them to Mexico, rather than sell him. Bass pins them down with sniper fire, forcing them to let loose the packhorse carrying the furs. He is ambushed, however, and the scalphunters recover the furs and proceed on their way. Approaching their camp at night, Bass tries to persuade Lee to help him, but the slave is now set on going to Mexico and refuses him assistance. Bass kills several of the scalphunters by starting a rock slide in the mountains. Then he contaminates the water of a nearby creek with locoweed, a toxic plant that causes the scalphunters' horses to run and buck wildly after they drink the water. They send Lee as a go-between to Bass, telling him he can keep the furs. A wary Bass comes down to collect the lone packhorse, but is ambushed by Howie. In an ensuing struggle, Howie is shot dead by Lee. The bickering Bass and Lee then fight, but neither can beat the other. Meanwhile, Kiowas attack and overrun the scalphunters. Two Crows, who had survived the earlier massacre, has fetched reinforcements. He takes back the furs. Bass and Lee, now friends, prepare to follow the Kiowas to take back the furs.
