Sunset Carson, ace driver for the Harding Stagecoach Line, persuades his boss Frank Harding (Edmund Cobb) to hire his brother, Jeff (Bob Steele), recently released from the penitentiary. Sunset isn't aware that Jeff owes his release to Marc Redmond (Tristram Coffin), owner of the rival line, and that Redmond is forcing Jeff to give him advance information when the Harding stages are carrying valuable shipments, so that his henchmen can rob the stage and force Harding out of business.

"VENGEANCE Beyond the RIO GRANDE!"