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

(Chapter 5)

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.

A cowboy discovers an advanced civilization living under his ranch. (Chapter 1)

Gene tries to stop the radium bomb sent by the Queen to kill the riders on the surface.