Bart Calhoun is the nephew of Wells Fargo agent Rand Malloy and is double-crossing his uncle by working with Duke Winslow. Duke and a henchman try to hold up the stage carrying a $30,000 payroll, but are foiled by Johnny, the company guard following on horseback. Bart and Duke report the failure to an angry Jeff Grant who is working on buying $30,000 worth of smuggled silver bars from Mexico to resell at a higher price in the States. Malloy is held up that night and killed, and Bart's watch fob found in his hand convinces Johnny that he was involved. With the aid of Malloy's daughter Tess and Malloy ranch-foreman Wade Shelton, Johnny runs down the culprits.