A singing cowboy stumbles across an ancient underground civilization beneath his ranch.

The Baxters leap to safety but are captured, and brought to Murania; Gene is unable to help, as the door control is disabled; the Baxters switch the door control, but get hit by radium rays.

(Chapter 5)

After defeating the guards, Gene reaches the surface and takes Beetson's airplane; the Queen kills the engine.

Gene is pulled to safety, and the Queen is rescued; the ray goes wild, destroying Murania; the Queen orders all to the surface, where everyone and the ranch are safe, while staying behind herself.