Stony Brooke's younger brother George, a hot-tempered but well-meaning cattleman, comes to the Three Mesquiteers' ranch, and after an initial misunderstanding with Tucson Smith, explains that he is being sought on a murder charge. George states that he is accused of murdering John Ashton, the influential leader of the sheepmen, in the ongoing war between the sheepmen and cattlemen of Silver City. George fled Silver City out of fear that John Harvey, Ashton's manager, and Harvey's stooge, Sheriff Dan Gray, would prevent him from getting a fair trial. Stony, Tucson and Lullaby Joslin, the other Mesquiteer, insist on escorting George back to Silver City and settling the matter. On the way, they see a poster advertising the auction of George's ranch and all his possessions to pay restitution to Ashton's daughter Sylvia. Stony tells George to hide in their secret cave, and while the Mesquiteers continue into town, Harvey rejoices that he will be able to get George's ranch, which has the best water in the valley. Harvey, who is the real killer, tries to pressure Sylvia to marry him, but she refuses and he goes to the auction. When the Mesquiteers arrive at the auction, Stony reveals that the deed to the ranch is in his name, not George's. While Harvey and Gray plot to find George, the Mesquiteers go to the ranch, where Stony's old friend Pete tells him that Harvey's gang is stealing all the best water and land away from the cattlemen. Pete suggests that Tucson run against Gray in the upcoming election for sheriff, sure that then not only will George get a fair trial, but that the cattlemen will have someone honest to help them. The Mesquiteers swing into action and soon have raised much support for Tucson. One afternoon, Stony meets Sylvia, and at first, when they do not know the other's identity, they flirt happily. When they arrive in town, however, Harvey tells her who Stony is and Sylvia treats him coldly. Later, Harvey's men succeed in capturing George but are prevented from hanging him when Sylvia insists that he be given a fair trial the next day. Stony tries to break George out of jail that night, but Sylvia again interferes, and Stony is incarcerated with George. Meanwhile, Tucson and Lullaby have ridden all night to round up the cattlemen, and the next morning they come to town to vote for Tucson. Harvey's gang attempts to keep everyone away from the polls, and a shootout begins between the factions. During the melee, Sylvia overhears Harvey and one of his men discussing Harvey's murder of her father. Sylvia leads Tucson to Stony and George, and soon the Mesquiteers have apprehended Harvey and the cattlemen have bested the gang. Later, Sylvia tells the Mesquiteers that she is selling her sheep to raise cattle, and they all share a laugh as a ram chases Lullaby.