Planet Earth is a devastated wasteland| and what's left of humanity has colonized the Moon in domed cities. Humanity's continued survival depends on ananti-radiation drug only available on planet Delta Three| which has been taken over by Omus| a brilliant but mad mechanic who places no value on human life. Omuswants to come to the Moon to rule and intends to attack it by ramming robot-controlled spaceships into the domes. Dr. John Caball| his son Jason| Jason's friend|Kim| and a robot named Sparks embark on Caball's space battlecruiser on an unauthorized mission to Delta Three to stop Omus.