The sixth film in Monograms Rough Rider series once again follows Buck Roberts (Buck Jones), Tom McCoy (Tim McCall), and Sandy Hopkins (Raymond Hatton) as undercover US Marshals posing as outlaws in order to confound their enemies. When Sandy is framed for murder by a gang of frontier racketeers who hope to take over a small town as their headquarters, Buck and Tom must work separately to save their buddy from a lynch mob and foil the crooks dastardly schemes.