The Phantom Empire

Introduces the characters and gives a view of the Muranian world where Queen Tika watches the action from her special viewing room. It ends with Gene and the kids falling from a cliff. A real cliffhanger!

Gene, Frankie, and Betsy are saved from certain death by the Junior Thunder Riders. During a stagecoach chase, Tom Baxter is killed. Gene is arrested, and Frankie and Betsy stow away on an airplane.

The Baxter kids escape from the plane by parachute, while Gene has joined the Thunder Riders. Queen Tika is angry that Gene has not been captured, Gene overhears Beetson confess to Baxter's murder.

Gene uses the Thunder Riders' clubhouse. He switches clothes with a Lieutenant and is caught by the Riders, and taken back to Murania. He is unmasked and ordered to the "Death Chamber" by Queen Tika.

Argo saves Gene by opening a trapdoor. Gene lands in a room where he overhears Muranian rebels who capture him, but he breaks free. Two of the Queen's guards activate two deadly robots to find Gene.

The torpedo explodes knocking Gene unconscious. Queen Tika knows there is a traitor, and orders Gene brought back. Gene gets into a swordfight with guards. Frankie and Betsy are trapped by Beetson.

Defeating the guards, Gene gets to the surface. Gene notices Baxter kids' signal fire. To make his broadcast, Gene flies to the ranch. Frankie rigs up a transmitter in the plane and Gene performs.

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.

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, she is shocked, but forms an alliance with him and orders death to Argo.

The Baxters find Gene in time to save him. Argo orders the death of all surface people. Battling, Gene arrives to where the Queen is being executed, but is knocked into the path of death-dealing rays.

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.