Martin Keene, who runs the town of Keenesburgh, is despised by the citizenry because of the heavy taxes he has levied against their lands. Consequently, when Judge Darcy arrives with news that the governor has called for an election to determine the new county seat, the populace is elated because if the town of Centerville wins the election, Keene will be deposed. Soon after, U.S. Marshal Sandy Hopkins arrives in Keeneburgh, posing as the new schoolteacher. Sheriff Tom Boyd has sent for Sandy to insure that the election will be honest. Deciding to install his own man as sheriff, Keene orders his thugs, Nate Todd and Lucky Cramer, to bushwack and kill Boyd, and then he sends for notorious gunman Wade Gunnerson to be the new sheriff. On the stage to Keenesburgh, Sandy's partner, marshal Nevada McKenzie, meets Gunnerson and Trooper Meade, an old soldier who detests Keene. When a local lawmen stops the stage to arrest Gunnerson for murder, Gunnerson shoots him. Calmly drawing his gun, Nevada kills Gunnerson and then assumes his identity. Upon arriving in town, Nevada introduces himself as Gunnerson, thus earning the enmity of Denny Boyd, the late sheriff's son. After alluding to Nevada that he has devised a plan to fix the election, Keene sends him to break up a meeting of the local ranchers. Following Keene's orders, Nevada confiscates the ranchers' stock in lieu of overdue taxes. Angered, Denny leads the local ranchers in a confrontation with Keene's thugs, but Nevada intervenes and quells the disturbance. Calling Denny and Keene to his office, the judge then outlines procedures to insure that the ballots from the outlying towns will be safely delivered. The judge assigns a man from each faction to accompany the ballots, and Lucky and Denny are appointed to bring them from Northfolk. On election day, Nevada has still not uncovered Keene's plans for fixing the election. Centerville takes an early lead in the vote tally and the town eagerly awaits the arrival of Denny and Lucky with the Northfolk ballots. As Denny and Lucky near town, several of Keene's men spring from the bushes and knock Denny unconscious. Just then, Nevada rides out of the underbrush and shoots the thugs before they can tamper with the ballots. Nevada and Denny then deliver the ballot box to town. Pinning on their marshal badges, Sandy and Nevada appoint Trooper as the new sheriff. Nevada then strides into Keene's office to demand his records, and when Keene pulls a gun, Nevada shoots him. After Sandy arrests the remainder of the gang, the ballots are counted and Centerville is declared the new county seat. Their mission completed, Sandy and Nevada ride their separate trails home.