Jimmy's father, a rancher, died in suspicious circumstances. To make things worse, Jimmy's disreputable uncle has a plot to take over the ranch. Jimmy turns to his friend Brad, the Marshal, for help.

An obscure entry in the musical Western cycle, Swing, Cowboy, Swing was produced by and starred country & western bandleader Cal Shrum. Shrum and his band, the Rhythm Rangers, are warned away from playing a theater in Big Bend by Cal's brother, Walt Shrum and his Colorado Hillbillies. Ignoring the warning, the Rhythm Rangers arrive at the theater only to be shot at by a masked stranger. With the help of stranded vaudeville performer Max "Alibi" Terhune and his dummy Elmer, Cal manages to catch the mystery shooter who turns out to be Frank Lawson (Frank Ellis). The film apparently did not generate enough interest for a series, but was re-released by Astor Pictures in 1949 under the title Bad Man From Big Bend.