A singing cowboy stumbles across an ancient underground civilization beneath his ranch.
Gene tries to stop the radium bomb sent by the Queen to kill the riders on the surface.
The Queen orders Gene to tell her who saved him, but he refuses; after Gene sees the kids, he tells the Queen that it was Argo; the Queen is shocked, but forms an alliance with him and orders death to Argo.
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.
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.