Upon riding into the small town of Occidental, Hack Williams, an ex-cavalryman, dismounts his horse near the stables. From the shadows, an Indian shoots another Indian seated peacefully by the side of the barn. Startled, Hack fires his rifle, sending the assassin scurrying away. Drawn by the sound of gunfire, the townsfolk assemble by the barn and accuse Hack of murdering the peaceful Indian. Fearful that the Indian's death will incite the tribe to attack, the town finds Hack guilty of murder and sentences him to hang. While awaiting his execution, Hack convinces his jailer to provide him with a bottle of whiskey. The next morning, the tribe appears and annihilates the entire town. Only Hack, drunk in his cell, is spared. Soon after, Nora Hayes, a proper Boston schoolteacher, arrives in town in a wagon driven by Charlie Martin, and the two are shocked to find the street littered with dead bodies. After Charlie is shot and killed by a wounded Indian, Nora presumes that she is alone until Hack, drunk and cackling, stumbles around the corner. When Nora asks Hack to escort her back to the stagecoach station, he warns her that the Indians will be waiting in ambush and offers to accompany her to a nearby settlement instead. Climbing back into Charlie's wagon, the two leave town and Hack continues his drinking spree. Hack's drunkenness and insolence offend the proper Nora, who questions why he left the cavalry. After the drunken Hack explains that he resigned because he hated killing, the pair camp for the night. Cold and frightened, Nora snuggles next to Hack for warmth and safety. The next morning, as they continue their journey, Nora pours out Hack's liquor supply. Upon reaching the settlement, the two are stunned to find that the entire town has been massacred. As Nora chastises Hack and compares him to her depraved father, Hack swerves around and shoots an Indian who is about to kill them. Shaken by the experience, Nora apologizes for her harsh words. Misfortune follows them as one of the horses goes lame and a wagon wheel fails. Forced to cross the desert on foot, their water supply depleted, the two suffer from thirst and exhaustion. Desperate, Hack suggests they pray and asks Nora to teach him how. After bowing their heads, they miraculously discover a pond nearby. Joyously immersing themselves in the water, the two embrace and emerge refreshed. They are about to continue their trek when Hack spots a lone rider in the distance. The man, a wounded trooper named Hadley, recognizes Hack from his cavalry days. With his dying breath, Hadley recounts that he was shot by Indians while on a scouting mission and begs Hack to warn the oncoming patrol that the warriors are waiting in ambush. Mounting Hadley's horse, Hack rides into the ambush, drawing gunfire. Alerted by the sound of gunshots, the troopers raise their pistols in defense, thus thwarting the attack. Wounded, Hack is taken to a doctor and recovers with Nora at his side. After Hack and Nora embrace and call each other by their Christian names for the first time, Col. Thurston enters the room and thanks Hack for his heroism, thus redeeming his career as a soldier.