Jack Armstrong

Heading an aviation company that develops atom-powered motors, Jim Fairfield (Pierre Watkin) learns from his chief scientists, Vic Hardy (Hugh Prosser), that cosmic radiations are

The heroic trio escape when the door to the trapped room is blown open by the force of the explosion. By triangulating the cosmic rays, Jack determines the the experiments are taking a toll.

Jack Armstrong saves himself and his friends by forcing the plane into a a belly landing. Jason Grood (Charles Middleton), owner of the island's trading post and the brains behind it.

Jack and Betty are saved from the fiery pit by Umala (Russ Vincent), a native who now realizes that his enemies are the white men working for Grood. The latter orders his henchmen to do his bidding.

Jack and his friends land on a rocky ledge and make their way to the ground below. Meanwhile, Grood plans a fantastic demonstration to impress the natives.

As the aeroglobe settles in its berth, Jack and the Fairfields flatten themselves against the walls of the pit and escape death. Princess Alura, is believing Xalta.

Jack retains consciousness long enough to douse the poison gas bomb with sand, saving himself and Uncle Jim. Later, Pierce joins them, still pretending friendship, to look for Vic Hardy.

Betty reaches the well just in time to save Jack, Uncle Jim, and Billy. Uncle Jim then decides to confront Grood, now suspected to be the brains behind the terrible scheme.

Jack and Uncle Jim who have been trailing the truck are set upon by Grood's henchmen. The timely arrival of Umala and friendly natives saves the situation' Billy is rescued.

The knives fly wild when two shots ring out. Uncle Jim arrived with Billy and Umala just in time. But they are surrounded by hostile natives, after a fight between Umala and Naga.

The beam is deflected when Jack and Billy attack and overpower the henchmen operating the Annihilator. Pierce and his men, now opposed to Grood, wrestle the gun away from Jack.

Jack, unharmed by the fall, escapes his opponent, commandeers Grood's truck and rescues Uncle Jim and Billy. They cannot carry off the Beam Gun, but take the activator tube.

The figure in the path of the death ray was Pierce and he was killed, Grood's henchmen capture Jack and Uncle Jim and take them to the laboratory. But Vic Hardy is there, and he knows.

Struggling with one of the guards, Jack had fallen to the ground before the truck went over the cliff and destroyed the infamous Beam Gun.

Jack parachutes to safety as the Areoglobe explodes, killing Zorn and other Grood henchmen and destroying the master death machine. Vic Hardy regains consciousness.