When Jim Drummond refuses to sell his ranch to J. R. Rankin, a crooked land agent representing the railroad, Rankin plots to frame Jim for the murder of William, a neighboring rancher. After Rankin's man, Monk Saunders, shoots Williams in the back, Greeley, another Rankin henchman, testifies that he witnessed Jim shoot Williams. Jim is arrested and taken to the town of Blue Mesa for trial, but as his stagecoach nears town, Rankin's men bushwack it. In the ensuing shootout, the sheriff, the coach driver and Curly Yantis, a notorious gunslinger riding passenger on the coach, are killed. Jim survives and is joined by his friends Whopper and Smokey, who tell him that Rankin has seized his ranch. To investigate Rankin's treachery, Jim decides to pose as Curly and rides to Blue Mesa, where Rankin enlists him as a hired gun. Meanwhile, Whopper and Smokey join forces with the ranchers' protective association, which is led by Roy Tremaine and his daughter Alice. To thwart Tremaine, Rankin buys the rancher's $10,000 note from the bank and threatens to foreclose unless the mortgage is paid immediately. When Jim, the sheriff and Sam Daggett, another of Rankin's men, ride to the Tremaine ranch to collect the money, Tremaine offers them $5,000 that the ranchers have raised. Jim tricks Daggett into taking the money to Rankin, and on the road to town, Smokey and Whopper rob Daggett and give the money to Tremaine, who then presents it to Rankin as the balance of his debt. When Frank Higgins, another victim of Rankin's misleadings, demands payment for his ranch, Rankin convinces him that Tremaine has double-crossed the ranchers and sold out to the railroad. Furious, Higgins rides to the Tremaine ranch, where Monk and Greeley shoot him in the back and frame Tremaine for his murder. After Tremaine is arrested, Jim takes Greeley and Monk prisoner and tells Whopper and Smokey to hold them at his ranch until Tremaine's trial. When Alice realizes that Jim is on the side of law and order, she apologizes for having doubted him. At Jim's ranch, Whopper locks Monk in a back room, where he escapes through a broken window. Upon discovering Monk's escape, Whopper terrorizes Greeley into signing a confession by pretending to beat Monk in the back room. Back in town, Jim is conferring with Rankin in his office when Monk rides in and exposes his true identity. Before Rankin can capture him, Jim gallops out of town and takes Smokey, Whopper and Greeley to the Tremaine ranch, where they find the murder weapon hidden in a well. Realizing that Rankin will try to prevent Greeley from testifying, Jim tells Smokey to assemble the ranchers' protective association while he sneaks into town with Greeley in the back of a wagon. At the trial, as the jury finds Tremaine guilty of murder, Jim bursts into the courtroom with the murder weapon and Greeley, who confesses all. After Daggett shoots Greeley, Rankin and his gang flee. At that moment, Smokey and the ranchers arrive to corral Rankin's men, while Jim captures Rankin and Daggett. When Colonel Lodge of the railroad learns of Rankin's duplicity, he returns the land to the ranchers, and all ends happily as Jim promises Alice to return to the Tremaine ranch.