The return of notorious outlaw Dingo Brion to the small town of Medicine Bend in the Colorado territory sets the townspeople gossiping and worries stern marshal Calem Ware, whom Brion has promised to kill. Brion's return coincides with the arrival of a theatrical group, headed by beautiful star Tally Dickinson, whom theater owner and businessman Hamer Thorne hopes to marry. While Calem is getting shaved at the barbershop, Brion bursts in and draws his gun, but Calem kills him with a derringer and stalks away, despite sarcastic barbs from saloon owner Cody Clark. Only Doc Amos Wynn and Calem's landlady, Molly Higgins, see how much the marshal is affected by the attack, but both remain silent. Later, wealthy Asaph Dean drives into town with his wife Cora, who is having a secret romance with Thorne. Asaph meets with Calem to reassure the marshal that keeping Medicine Bend law-abiding will help Colorado achieve statehood. Doc brings Brion's effects to Calem, and the men agree that the hundred dollars found on the body prove that Brion was hired to kill Calem. Brion's widow and brother Dooley then come into town, and Dooley, who abhors gun violence, declares he bares no grudge against Calem, but refuses to take the hundred dollars. That evening at the dance hall show, Calem meets Tally in her dressing room and they are reunited after nine years. Unknown to everyone, Calem and Tally are married, but, as she was unable to accept Calem's violent lifestyle, she left him while still in love with him. The reunion is interrupted when Calem learns that Dooley is wrecking Clark's saloon, insulted by the town-wide collection of money made on the Brions' behalf at Calem's request. Calem and Dooley fight viciously until Dooley relents and is arrested. Tally views part of the brawl and is dismayed that Calem's life has not changed. A few days later, gunslinger Harley Baskam rides into town at the behest of Thorne and Clark, who hire him to kill Calem. Although Baskam has his own grudge against Calem, he asks the men why they want Calem killed, and Thorne explains that they hope to take over Medicine Bend in anticipation of a mining boom and fear that Calem will interfere. Although upset by Baskam's demand for one-third of the mining profits, Thorne and Clark eventually agree to the proposal. Mrs. Brion pleads for Dooley's release from jail, which Calem grants. Shortly afterward, Calem is nearly struck by a knife thrown by Juan Tobrez, who then dashes to Clark, claiming he hoped to get paid like Brion. Instead Clark kills Juan, and when Tally witnesses the threats exchanged by Calem and Clark, she makes reservations on the next stage out of town. She then informs Calem that she can no longer stay married to him because he continues to embrace violence, and will file for divorce in Chicago. That evening in Clark's saloon, Calem confronts Baskam, who shoots the marshal in the head. Doc declares Calem dead and Thorne and Clark immediately encourage the townspeople to celebrate. When Tally hears the news and sees the mayhem filling the streets, she weeps, finally understanding Calem's significance to the town. Thorne and Clark swiftly coerce all of the town's businesses to sell out to them and promote gambling and drinking with promises of employment at the new mines. Thorne rides out to Asaph's ranch to report Calem's death and advises him to stay out of town. Asaph laments the fall of Medicine Bend, and when Cora overhears Thorne blithely dismiss their affair, she goes into town. Doc informs her that Calem is dead, and Cora decries her foolishness for not taking action despite knowing about Thorne and Clark's plans for months. When Doc asks if she would testify against Thorne and Clark, Cora vows she will. The next day as Molly packs up Calem's clothes, Tally looks around his modest room and is surprised when Molly details Calem's goodness and long suffering to maintain order in the town. Later, Doc tells Tally that Calem is still alive, having only suffered a flesh wound, and is hidden at the jail, guarded by Dooley. When Tally insists she is still leaving town, Doc claims she is not good enough for Calem. Later, Tally comes to the jail, but Calem refuses to see her. That night, a restored Calem, hearing all the carousing in the streets, returns to town and begins closing down the gambling parlors and saloons. At Clark's saloon, Thorne and Clark quickly abandon Baskam upon learning of Calem's resurrection. Calem demands Baskam's surrender and when he refuses, dives into the saloon and kills him. Realizing that their hasty attempt to corrupt the town is crumbling, Thorne and Clark make plans to escape. Hearing Calem approaching the opera house, Thorne arms himself, but Calem hides when Clark arrives and Thorne accidentally kills his partner. Meanwhile, Asaph has rounded up the law-abiding citizens, who prevent Thorne from fleeing. When Asaph apologizes to Calem for forcing him to handle the town's problems single-handedly and vows to help, Calem presents him with his marshal's badge and declares that Asaph and Medicine Bend no longer need him if they realize that they can look after themselves. The next day, Molly and Doc see Calem and Tally off as they head for their new life on a ranch.