Outside the town of Nacional, J. R. P. W. J. D. "Johnny" Rapidan and his sidekick, Frog, find a young man lying on the ground, near death. After taking him home and reviving him, Johnny visits Alford "Barfoot" Jennings, the town's crooked lawyer, in an attempt to work out the details of recently arranged ranch swap between Johnny and his friend, local rancher Bill Smith. Johnny distrusts Barfoot, who informs him that Smith has been killed by fugitive Jim Terril, and therefore Johnny will have to talk to the ranch's new owner, Señor Louis Alarcon. Before leaving, Johnny buys an old rifle he spies in the lawyer's office, and then, outside, sees Sheriff Law and his deputies ruthlessly pursuing a limping, masked man, and helps the man escape. Returning to his camp, Johnny realizes that the young man he has rescued must be the fugitive Jim Terril and helps him get away. The next day, when Johnny and Frog visit Alarcon to discuss a mortgage, they see the limping, masked man's horse outside Alarcon's mansion and then notice that, like the masked man, Alarcon limps. Inside the house, Johnny hears a familiar cough and suspects that Smith is there, but Alarcon denies it. When they return to their ranch, Law is there, and accuses Johnny of having abetted the thief who robbed the Esperanza Mines paymaster. As the abetter was shot in the leg, however, Law is forced to leave when Johnny proves that he has not been shot. Soon after, Jim returns to Johnny's house with a bullet in his leg, and confesses that he has been taking the blame for Smith's murder but thinks his brother Terry actually killed Smith in revenge for the murder of their oldest brother Paul. He also says that he was on his way to jail when a masked man helped him flee. Johnny reveals that he thinks Smith is alive, and urges the boy to hide out on his ranch while he investigates the mystery. At Alarcon's the next day, Law arrives to search for Jim, prompting Alarcon to order his daughter Vega to arrange for the escape of a man hiding in their house, whom Vega assumes is her friend, Jim. Johnny visits and sees her preparing a horse, but before he can discover who the horse is for, Law sneaks up on him and arrests him for trespassing. Johnny quickly escapes, however, and flees to his ranch. In town, meanwhile, a stranger pays Barfoot to find the man who bought the rifle from him, and the lawyer, who now suspects that Johnny is a wanted man, visits him and attempts to blackmail him. After throwing Barfoot off his ranch, Johnny goes to Alarcon's house, where he finds a bag labeled Esperanza Mines on his lawn and decides to spy on the house from outside. Inside, Vega, who is entertaining her suitor, John Emerson, bumps into Smith, who indeed has faked his death and is hiding out at Alarcon's, and screams. Her father tells her that he must continue to help Smith or his honor will be ruined, but Vega worries that Jim will be harmed for something he has not done. When Smith runs away, Johnny chases and captures him and brings him back to Alarcon's, where Smith, whose real name is Hefty Gurlach, discloses that it was Emerson, actually a criminal named Blackie Mason, who robbed the mines. After Emerson escapes out the window, Johnny and Frog bring Smith back to their ranch, where Law soon arrives to arrest them. As soon as they convince the sheriff to come inside and see that Smith is alive, Alarcon sneaks into the house and helps Smith flee out the back. Smith runs back to Alarcon's and is followed by everyone, including Emerson, who harbors a vendetta against Smith for a past double-cross. In an ensuing gunfight, Smith is shot, but, before dying, reveals that he killed Terry and that his old acquaintance Alarcon covered for him so he would not reveal that Alarcon was not an aristocrat but merely the son of a servant. Later, as Johnny tells the whole story to Law, Barfoot brings in the stranger, who turns out to be Johnny's brother Dick. Johnny has been covering for Dick, thinking he shot someone with the rifle Johnny saw in Barfoot's office, but Dick reveals that he is actually innocent, and the brothers are finally reunited.
