Ne'er-do-well Tom Newcombe is publicly hanged for murdering a woman because the local school teacher, Celia Ames (Colleen Dewhurst), refuses to alibi him. A mysterious man, Paul Taylor (Hugh O'Brien), comes to town, signs on to work as a Shiloh Ranch hand and begins romancing Celia. However, his odd behaviour begins to raise the suspicions of Judge Garth and the local Sheriff who wonder about the motives of the stranger.

The owners of the Bradford and Willson Transportation Co. had been contracted to build a railway line for Judge Garth and other investors but had been procrastinating in starting the project. When the Judge threatens them with legal action, they send a woman, Mrs. Wallace (Vera Miles), to spy on the Judge by becoming Betsy Garth's private tutor. Matters become complicated when the Judge falls in love with Mrs. Wallace. They become even more complicated when the Judge shoots in self-defence, Willson (David White), but can convince no one, including the police, that the man is dead.

Judge Garth and Betsy are among the passengers on an overcrowded stage which is waylaid by an outlaw gang led by Pauk (Paul Richards). The passengers are trapped in a way station and the outlaws demand that one of the male passengers, a George Wilson who is traveling incognito, be given to them. Wilson is a former outlaw who had betrayed the gang. The various passengers must decide whether to live with their consciences and hand Wilson over, or risk their own lives in a gun battle with the desperate gang.