Former Marshal Jack Rowan had hopes to put away his guns forever when he buys a cattle ranch near the Mexican border, but he discovers that Mexican cattle are being smuggled across the border by way of his ranch. Jack stops at the store run by John Howard to get supplies and meets Carol Howard, the storekeeper's niece. Jack sees Taylor, a suspected rustler, follow Frank Stone into his office. He overhears Taylor tell Stone that the Sheriff has caught one of the cattle smugglers, but he has named Jack as the gang leader. They capture the listening Jack and go for the sheriff. Stone brags to Howard and Carol that he has Jack a prisoner, Carol and Jack's sidekick Manny free Jack. Jack and Manny trail Taylor and see him pay for cattle to be smuggled into the Texas. Manny goes for the Sheriff while Jack hides outside the tunnel, used by the smugglers, and forces a gun battle.