In the 1880s, Gene Barry as Wes Bonell, Barry Sullivan as Griff Bonell, and Robert Dix as Chico Bonell ride into Tombstone, a rough town in Cochise County, Arizona. Griff is a reformed gunslinger now working for the Attorney General, tasked with arresting Howard Swain for mail robbery. Barbara Stanwyck as Jessica Drummond, a landowner who rules the territory with an iron fist, keeps the town in fear through her forty hired guns and a loyal circle that includes her brother Brockie Drummond.
The drama intensifies when Brockie, an arrogant drunk and bully, pushes the town to the edge. He and his drunken friends trash the streets, until a tense confrontation erupts: Brockie shoots the vision-impaired town Marshal John Chisum in the leg, and the disorder spirals. Griff steps forward, pistol-whipping Brockie in a single blow while Wes covers him from the gunsmith shop with a rifle, aiming to avoid unnecessary killing. Jessica’s family history adds weight to the collision of loyalties—she delivered Brockie when their mother gave birth for the last time, a detail that echoes through the town’s tangled loyalties.
Wes finds himself drawn to Louvenia Spanger, the daughter of the town gunsmith, and decides to settle down, even as Griff becomes romantically involved with Jessica after she is dragged by a horse during a tornado. The romantic entanglements intensify the stakes as two of Jessica's forty dragoons, Ned Logan and Charlie Savage, try to ambush Griff in an alley. Chico intervenes just in time, saving Griff, and Savage is killed by Chico’s shot, further inflaming Jessica’s brother and her hired guns who seek to turn the town against the Bonnell brothers.
On Wes’s wedding day, tragedy strikes when Brockie shoots Wes, missing Griff as he leans forward to kiss the bride. Brockie is jailed for the murder, and Jessica spends every dime she has and pulls every string she can to save him, but the judge sentences him to hang. In a desperate bid for escape, Brockie uses Jessica as a shield and dares Griff to shoot; Griff’s shot wounds Jessica, and Brockie—true to his cowardly nature—becomes the first man Griff has had to kill in ten years.
With Brockie dead, Chico stays behind to take the marshal’s job, while Griff heads for California, convinced that Jessica hates him for taking her brother’s life. Yet she chases after his buckboard, shouting his name, and the two ride off together into an uncertain future, leaving Tombstone behind as a chapter closed and another began.
