The film’s story revolves around the Paiute Native American outlaw Willie Boy (Robert Blake), who escapes with his lover, Lola (Katharine Ross), after killing her father in self defense. According to tribal custom Willie can then claim Lola as his wife. According to the law, Deputy Sheriff Cooper (Robert Redford) is required to charge him with murder.
Willie Boy and Lola are hunted for several days by a posse led by Cooper. Willie manages to repel the posse’s advance when he ambushes them from the top of Ruby Mountain. He only tries to shoot their horses, but ends up accidentally killing a bounty hunter, resulting in another murder charge.
Days later, as the posse closes in, Lola dies by a gunshot wound to the chest. It is left deliberately ambiguous whether Lola shot herself in order to slow down the posse’s advance or whether Willie killed her to keep her out of the posse’s hands. Cooper is inclined to believe the latter and then goes off ahead of the posse to bring in Willie dead or alive. As soon as Cooper catches up, he comes under fire from Willie, who is positioned at the top of Ruby Mountain. Cooper narrowly avoids being shot on several occasions.
In the film’s climax, Cooper maneuvers behind Willie, who has donned a ghost shirt, and tells him he can turn around if he wants to, which he does. The two pause before Willie raises his rifle at Cooper, who beats him to the draw and shoots him. Fatally struck in the chest, Willie tumbles down the hillside. Cooper picks up Willie’s gun and finds that it wasn’t even loaded, making it apparent that Willie deliberately chose death over capture. Abashed, Cooper carries the slain outlaw the rest of the way down Ruby Mountain and delivers him to other Paiutes, who carry the corpse away and burn the remains.
When confronted by the county sheriff, Cooper is told that the burning of Willie’s body will ruin the people’s chance to see Willie in the (now-dead) flesh, denying them the ability “to see something”. Cooper retorts: “Tell them we’re all out of souvenirs”.