Earth is menaced by an evil alien "Ruler" who desires to add the Earth to his list of conquests. The Ruler uses a number of diabolical devices to carry out a series of attacks against the Earth. These devices generate floods and typhoons, spread germ warfare, block out the sun, generate additional suns, and pull the Earth and the moon out of their orbits. Scientist Commando Cody develops a "Cosmic Dust Blanket" to protect the Earth. However, the Ruler uses guided missiles to penetrate the shield. Cody, assisted by Joan Gilbert and Ted Richards, constructs an atomic-powered rocketship to travel into space and combat the Ruler and his evil henchmen and robots.