Pop "Brimstone" Courteen (Walter Brennan) and his sons, Nick, Luke and Bud, run a ranch outside the town of Gunsight, and are none too happy about the recent arrival of homesteaders in the area. Determined to cut off the interlopers' supplies, the Courteens rob incoming stagecoaches and even the local bank. But things change when a U.S. marshal (Rod Cameron) arrives in town to investigate, and Bud falls in love with one of the hated homesteaders.