When the ancient continent of Mu sank beneath the ocean, some of its inhabitant survived in caverns beneath the sea. Cowboy singer Gene Autry stumbles upon the civilization, now buried beneath his own Radio Ranch. The Muranians have developed technology and weaponry such as television and ray guns. Their rich supply of radium draws unscrupulous speculators from the surface. The peaceful civilization of the Muranians is corrupted by the greed from above, and it becomes Autry's task to prevent all-out war, ideally without disrupting his regular radio show.
Gene Autry
as Gene Autry
Frankie Darro
as Frankie Baxter
Betsy King Ross
as Betsy Baxter
Dorothy Christy
as Queen Tika
Wheeler Oakman
as Lord Argo
Charles K. French
as Mal
Warner Richmond
as Rab
J. Frank Glendon
as Prof. Beetson (as Frank Glendon)
Smiley Burnette
as Oscar (as Lester 'Smiley' Burnett)
Peter Potter
as Pete (as William Moore)
Edward Peil Sr.
as Cooper (as Edward Piel Sr.)
Jack Carlyle
as Saunders
