Tom Sabin, wanted for the murder of Jay Cassavedas, is riding toward the town of Purgatory when he is stopped by Haggerty, a noted "town tamer" who threw him out of Kansas and now intends to bring law and order to Purgatory. When Tom refuses to avoid Purgatory, Haggerty tries to shoot his gun hand, forcing Tom to kill him. Tom then travels to Purgatory, where the townspeople accept his story that Haggerty sent him, and offer him their collection of cash to rid the town of the crooked businessman who runs the town, saloon owner Hoag. Tom agrees to take the job, but requests that the money be sent to Cassavedas' widow. As Tom peerswo into Hoag's saloon, Hoag receives a statue of the Venus de Milo, which he proudly places on his piano. Tom admires the most beautiful woman in the room, but upon learning that she is Hoag's wife Mary, leaves to set up his headquarters in the former marshal's office. Hoag sends his henchman, Grady, to the office to kill Tom, but Tom easily shoots him first. Noting a wanted poster on the wall bearing his image, Tom takes it down, then wakes Dipper, the local drunkard who lives in the jail. Dipper recognizes Tom from the wanted poster, and informs him that Hoag is unstoppable. Tom soon learns why, when he visits the saloon that night to confront Hoag about recent castle rustling activities, and discovers that Hoag is confined to a wheelchair. Knowing that the Western code does not allow a man to shoot someone who is handicapped, Hoag brazenly informs Tom that he has sent for the three fastest guns in the area, Quijano, Farmer Brown and Johnny Naco. Tom then instructs Dipper to visit Marshal Becker in the next town to request a legal injunction against Hoag. Before leaving, Dipper holds a secret vote to name Tom marshal, and even though the vote fails, Tom is furious at the idea. Dipper then becomes drunk and disorderly in the saloon, prompting Hoag to insist that Tom arrest him. Mary visits the jail and reveals that Hoag broke his back in a stagecoach accident while they were engaged, and she has stayed by him ever since. The next day, Dipper heads for Marshal Becker's, passing Quijano along the way. Although the outlaw is cordial, Dipper soon discovers Becker's dead body on the trail and realizes that Quijano is a gunslinger. In town later, Mary secretly offers Quijano money to leave, but he explains that he hates town tamers and will not back down. When he draws on Tom in the saloon soon after, Tom kills him with one shot. The next day, while Brown and Johnny both head for Purgatory, Mary warns Tom that Hoag cannot be stopped, then asks the lawman to accompany her on a moonlit walk. Tom suspects that the isolated walk may be a trap, and although Mary proclaims her affection for him, Tom's jumpiness insults her, and she stalks away. Back in town, Tom spots Hoag's bartender harassing Dipper and instigates a long brawl, which Tom eventually wins. While tending to Tom's wounds, the town doctor notes that he saw Mary take him down a lover's lane, prompting Tom to realize her feelings for him. Meanwhile, Mary finds Brown in the street and pleads with him to leave. Ignoring her entreaties, Brown plots with Hoag to entice Tom into a poker game, during which Brown will conceal his gun and shoot Tom under the table. Even with this unfair advantage, however, Tom manages to shoot down Brown, causing Hoag to panic. When Johnny arrives, Hoag offers him three times the original price on Tom's head, and although the charming killer is confident of his ability to best Tom, when he sees him, both men back down. The townspeople scoff at Tom's apparent lack of courage, but Johnny soon reveals to Hoag that the two are brothers. When Mary questions Johnny, he admits that Tom took the blame after Johnny killed Cassavedas, and agrees to Mary's plan to run Tom out of town instead of shooting him. Tom acquiesces to Johnny's order to leave, prompting the townsmen to jeer and Mary to cry. Johnny, horrified to see his brave brother shamed, takes out his anger by fatally shooting Hoag in the chest. Mary pulls out a shotgun to avenge her husband, and although Johnny does not want to shoot her, he is about to defend himself when Tom returns to the saloon. As Mary drops the gun, Tom admits he cannot back down, and the brothers draw against each other. Tom wins the shootout, earning himself the title of the fastest gun in the West. After laying out his brother's body in the jailhouse, Tom refuses the town's offer to stay on as sheriff, instead pinning the star on Dipper. As he leaves, he declares his intent to begin again in Tombstone, and Mary vows to meet him there.