 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 an anti-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. Omus wants 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.