Gene (Gene Autry) is a singing cowboy happily running a radio station that happens to be located just above a mystical subterranean city. Conniving scientists discover the city and its rich deposits of radium ore and make plans to invade the underground world -- but first they must knock Gene out of the picture. The cowboy is not easily discouraged, however, and he enters the depths with his young sidekicks Frankie (Frankie Darro) and Betsy (Betsy King Ross) in order to set things right.
When withered Sheriff Doniphon (William Farnum) is overwhelmed by his town's drastic rise in cattle rustling, he calls on his deputy, cowboy Gene Autry (Gene Autry), for help. But Autry is bewildered when he discovers that these crafty thieves are utilizing new innovations -- from shortwave radio...
A traveling musician (Gene Austin) tries to prevent a rancher (Walter Wills) from losing his property to a swindler (Karl Hackett)
When his father is killed in a train wreck, a lad vows to find 'The Wrecker' who has been causing deadly accidents on the railroad.