In 1895, when the citizens of Coldriver, Colorado are overwhelmed by Smoke Denton's murderous gang, they ask Tom Holden to return as their marshal, a post he left fifteen years previously. Needing money to develop a valuable mine claim, Holden takes the job and brings along his sons, Tommy and Jerry. Meanwhile, banker Uriah Martin welcomes the arrival of his son Phillip and his ward, Dorothy Russell, whom he intends to marry to Phillip after embezzling her inheritance. Holden tells Martin, who is the secret leader of Smoke's gang, about his claim, and upon learning that Holden has not told even Tommy and Jerry about it, Martin tricks Holden into signing over the deed to him. Martin then orders Smoke to raid the miners' camp and kill Holden during the fracas. After Holden is murdered, Martin, who is the administrator of his estate, reads his will to Tommy, Jerry and Dorothy, whom he has called as a witness. Holden's will reveals that many years before he killed a notorious outlaw named Bart Clancy and then adopted Clancy's young son Jerry as his own. When Martin tells them that he has taken Holden's mine as payment for a debt, Jerry angrily accuses him of having stolen it. Later that day, Tommy confronts Jerry, who states that he must leave and clear people's suspicions about him now that they know his true parentage. Jerry also reveals that he knows that Tommy and Dorothy are in love, and wishes Tommy well in his new job as marshal. Jerry then goes to the town saloon, where one of Smoke's men, John Taggart, goads him into a fistfight. Taggart is killed when he falls and strikes his head, and Tommy is forced to arrest Jerry. The gang gives perjured testimony to make it seem as if Jerry deliberately killed Taggart, and Jerry is convicted. Judge Tater helps Jerry escape, however, and in order to learn more about Martin, Jerry accepts Smoke's invitation to join the gang. One day, Jerry, whom Smoke has dubbed "The Sombrero Kid," reads in a newspaper that Martin has refused Dorothy and Tommy permission to marry. After Jerry forces Judge Tater to marry the couple at gunpoint, he gets the cowardly Phillip to admit that Martin was behind Holden's death and that he stole the mine. Jerry and Tater succeed in getting the deed from Martin's safe, then are chased by the gang to Tater's general store, where they are joined by Tommy. Jerry explains everything to Tommy, and the brothers shoot it out with the gang. Jerry shoots Smoke, and as the townspeople round up the rest of the gang, Jerry takes Phillip to Martin, who shoots his own son to prevent him from talking. Martin is captured, and soon after, a new trial clears Jerry of Taggart's death. Jerry is appointed town marshal, and Tommy and Dorothy prepare to run the mine.