Robert Saunders, the wheelchair-bound editor of Mesa Grande’s newspaper, sends word to Hopalong Cassidy, asking him to help bring law and order to the town. After Peg Leg Holden, an old miner, discovers gold on his claim, he is ruthlessly murdered. Saunders’ editorial on the murder prompts Blackie, the current corrupt marshal, to lead a gang of drunken citizens to laughingly elect Saunders as the new marshal. Hoppy arrives in the area with his young brother Buddy and rescues Lilli Marsh, the owner of the Crystal Slipper saloon, from her runaway horse. Just before Hoppy and Buddy ride into town Bob Claiborne, Lilli’s cohort, orders Blackie to “teach Saunders a lesson.” Blackie ropes Saunders’ wheelchair and drags him through town, killing him. After he learns of the murder, Hoppy reunites with his old pal Windy Halliday, appoints himself marshal, and declares war against the outlaws. He discovers Lilli is the real head of the gang after she takes over Peg Leg’s claim. Hoppy arrests a man guarding the claim, but Lilli has him killed before he can reveal any information. After Hoppy determines that Lilli’s gold ore definitely came from Peg Leg’s mine, he plans to make some arrests and advises her to leave town, but she refuses. Hoppy arrests Claiborne for brandishing a gun in public, and while in jail, Claiborne confesses that Blackie is a murderer and gives the location of their hideout. With the help of neighboring ranchers and Windy, Hoppy rides out to the hideout and a gunfight ensues. Buddy is captured, but Hoppy saves him and arrests the outlaws. At Lilli’s saloon, Lilli struggles with Blackie, who plans to shoot Hoppy from a window, and she is shot. Hoppy sneaks in and kills Blackie, after which Lilli dies in his arms. Buddy remains in town with his newfound love, Mary Saunders, while Hoppy and Windy leave Mesa Grande, having restored law and order. More on Wikipedia or Mubi
Watch Hopalong Cassidy Returns (1936)