Gabby Hayes is not yet the sidekick in "Call of the Prairie," but he plays one of the heavies, Shanghai McHenry, while the future looks dim for junior sidekick Johnny Nelson (Jimmy Ellison). Johnny is framed by Shanghai's gang for the robbery and murder of the Bar-20 boss and, complicating the situation, falls in love with a beautiful girl who happens to be Shanghai's daughter! Can Hopalong Cassidy (William Boyd) save the day? Hopalong runs into crooked rancher Trumbull, who is trying to keep decent people from building a fence on their property in "Heart of the West." Determined to drive his stolen cattle, the rancher locks horns with the Jordan family and sends a stolen stampede towards our heroes.