The Phantom Empire
Gene Autry, playing himself, runs Radio Ranch, from which at 2pm everyday he makes a live radio broadcast.
Deep beneath Gene Autry's ranch live the survivors of the lost continent of Mu, which sank beneath the ocean.
Gene Autry accidentally discovers the Muranians, who are a highly advanced race, with superior weapons like ray guns and have also invented television!!
The Muranians huge supply of radium, soon brings them trouble from the surface.