Plot
In Hadleyville, a small town in New Mexico Territory, Marshal Will Kane, newly married to Amy Fowler, prepares to retire. The happy couple will soon depart to raise a family and run a store in another town. However, word arrives that Frank Miller, a vicious outlaw whom Kane sent to prison, has been released and will arrive by the noon train, one day ahead of the new marshal. Frank threatened revenge on Kane and the judge at his sentencing. Miller's gang—his younger brother Ben, Jack Colby, and Jim Pierce—wait at the station.
Amy, a devout Quaker and pacifist, urges Kane to leave town, but Kane refuses, knowing that Miller would still pursue him. Amy decides to leave on the noon train with or without her husband.
Kane visits old friends and allies, but none can or will help. Judge Percy Mettrick, who sentenced Miller, flees and urges Kane to do the same. Harvey Pell, Kane's young deputy, is bitter that Kane did not recommend him as his successor; he says he will stand with Kane only if Kane "puts the word in" for him with the city fathers. When Kane refuses, Pell turns in his badge and pistol. Kane's efforts to round up a posse at Ramírez's saloon and the church are met with fear and hostility. Some townspeople, worried that a gunfight would damage the town's reputation, urge Kane to avoid the confrontation. Some are Miller's friends, but others resent Kane for cleaning up the town in the first place. Others believe that Kane's fight is not the town's responsibility. Sam Fuller hides in his house, forcing his wife, Mildred, to tell Kane he is not home. Jimmy offers to help, but he is blind in one eye, sweating, and unsteady. The pastor of the local church, whose service was interrupted by Kane seeking help from the parishioners, is of no aid. Neither are some apparently willing volunteers, after the mayor encourages Kane to leave town. Martin Howe, Kane's predecessor, is too old and arthritic. Herb Baker agrees to be deputized, but backs out when he realizes he is the only volunteer. One last offer of help comes from 14-year-old Johnny. Kane admires his courage but refuses his aid.
While waiting at the hotel for the train, Amy confronts Helen Ramírez, who was once Miller's lover, then Kane's, then Pell's. Amy believes the reason Kane refuses to leave town is that he wants to protect Helen, but Helen reveals there is no lingering attachment on Kane's part, and she, too, is leaving. When Helen questions why Amy will not stay with Kane, Amy explains that both her brother and father were gunned down by criminals, a tragedy that converted her to Quakerism. Helen nonetheless chides Amy for not standing by her husband in his hour of need, saying that if she were in Amy's place, she would take up a gun and fight alongside Kane.
Pell saddles a horse and tries to persuade Kane to take it. They end up in a fist fight. After knocking Pell senseless, Kane returns to his office to write out his will. As the clock ticks toward noon, Kane goes into the street to face Miller and his gang. Amy and Helen ride by on a wagon, bound for the train. The train arrives, and Miller steps off as the two ladies board.
Kane walks down the deserted main street alone. He manages to kill Frank Miller's brother, Ben, in the opening salvo. Just before the train departs, Amy hears the gunfire and runs back to town. Kane takes refuge in a stable, and Colby is killed when he comes in after him. Miller sets fire to the stable to flush him out. Kane frees the horses and tries to escape on one, only to be shot off and cornered. Despite her religious beliefs, Amy picks up Pell's pistol and shoots Pierce from behind, leaving only Frank Miller, who grabs Amy as a human shield to force Kane into the open. When Amy claws Miller's face, he pushes her to the ground, and Kane shoots him dead.
The couple embraces. As the townspeople emerge, Kane smiles at Johnny, but looks angrily at the rest of the crowd. He drops his marshal's star to the street and departs with Amy. The townspeople look on in stunned silence.
