In the early 1900s, Wes Anderson is arrested for night-time cattle rustling (moonlighting). He had been gone from his home town for five years, leaving his sweetheart, Rela, to wait for him. Wes' brother, Tom, has chosen a different path in life and works as a teller in a bank in Rio Hondo. Tom is in-love with Rela and he pressures her to marry him in Wes' absence. Languishing in a sheriff's jail, Wes is awaiting trial, which promises to be a fair one, at least according to the town sheriff. But an angry lynch mob of local ranchers agitate in front of the jail, swinging a hanging rope and hankering for Wes' blood. When the sheriff leaves his jail for a lunch-break, the mob breaks into the jail, grabs an imprisoned hobo by mistake and hangs him. The lynch-mob believes to have hung Wes but he is safe, in jail. After he escapes from jail, Wes vows revenge on the members of the lynch mob. During the following days, Wes raids the ranches of those who participated in the lynch mob. He burns their ranches and barns, kills their livestock and he gets into gunfights with the ranchers. Wounded during a raid, Wes runs home to his mother's house. There he heals his wounds, re-connects with his mother and brother and also meets with Rela. Wes is still in-love with her but she claims not to be interested anymore. She prefers marrying Wes' brother, Tom, who offers more security than Wes. However, when Tom looses his job at the bank, Wes lures him into a bank-robbing scheme. Angry at his former employer, Tom agrees to join his brother Wes in robbing the bank in Rio Hondo. Tom figures he could use the robbery money to marry Rela. A third man, outlaw Cole Gardner, joins the Anderson brothers in their plan. The robbery has unexpected hitches that sends the robbers into a mountain hideout. Some double-crosses occur and the sheriff's posse trails the robbers. In a last-minute twist, Rela asks the sheriff to deputize her with the rest of the posse and promises to bring the robbers to justice. Will Rela shoot the men she loves or Vice-Versa ?