The Phantom Empire #02 The Thunder Riders

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.

Wanting everyone off Radio Ranch so they can investigate in private, Beetson frames Gene for murder.

Gene Autry - Gene Autry,
Frankie Darro - Frankie Baxter,
Betsy King Ross - Betsy Baxter,
Dorothy Christy - Queen Tika,
Wheeler Oakman - Lord Argo,
Charles K. French – Mal,
Warner Richmond – Rab,
J. Frank Glendon - Professor Beetson,
Smiley Burnette – Oscar,
Peter Potter – Pete,
Edward Peil Sr. - Doctor Cooper,
Jack Carlyle – Saunders,