Former stock-car racer Rod Tillman is hired to serve as the getaway driver for a band of Nazi bikers and their shared girlfriend Linda, who intend to go on a crime spree for kicks. The police contact Rod and task him with becoming a stoolie so the bikers can be brought to justice.

When the leader of a vicious motorcycle gang finds a farmworker's son flirting with his woman, he beats the boy senseless, then kidnaps the farmworker's daughter.

Earth is invaded by an interstellar terrorist group, Big Fire (the Gargoyle Gang in the American version), led by Emperor Guillotine who spends most of his time in a multicolored space ship hidden at the bottom of Earth's ocean, from which he issues his orders. Big Fire is capturing scientists to create an army of monsters to conquer Earth. A boy named Daisaku Kusama (Johnny Sokko in the American version) and a young Unicorn agent named Jūrō Minami (Jerry Mano in the American version) are shipwrecked on an island after being attacked by a sea monster and subsequently captured by Big Fire. They flee to where a Pharaoh-like giant robot is being built by captive scientist Lucius Guardian, who gives Daisaku and Jūrō its control device. Guardian helps them escape before he is shot to death; before he dies, he triggers an atomic bomb which destroys the base. The radiation activates the robot, which now obeys only Daisaku.