Two investigators for a stagecoach company are assigned to find out why the company's stages keep being ambushed. They discover that the culprits are white men disguised as Indians, and they set out to discover who is behind the plot.

Government agents Jim Lane and Sierra Pete are sent to investigate the breakdown of the U.S. Mail delivery in the La Paz country, which is carried by the Overland Company operated by Tom Gilbert and his daughter Barbara. Aided by their friend, Buckskin Bill Burke, they discover that Frank Chadwick, using white renegades disguised as Indians, is behind the trouble as he wants the mail franchise owned by Gilbert's stage line.—Les Adams <[email protected]>