The Johnny Mack Brown West of Wyoming concerns the efforts by cattle baron Simon (Stanley Andrews) to prevent the opening up of the rang to homesteaders. Government agent Brown comes calling when Simon begins resorting to cold-blooded murder. The leading lady is Gail Davis, a few years shy of her Annie Oakley TV stardom. Surprisingly, West of Wyoming contains none of the comedy relief that had characterized earlier Johnny Mack Brown oaters.

When a woman attempts to kill her uncaring husband, prosecutor Adam Bonner gets the case. Unfortunately for him his wife Amanda (who happens to be a lawyer too) decides to defend the woman in court. Amanda uses everything she can to win the case and Adam gets mad about it. As a result, their perfect marriage is disturbed by everyday quarrels.