Emperor Guillotine gives Dr. Over a spaceship equipped with all kinds of scientific weapons. After landing at the earth, Over sends an electric monster called Sparky to the ground of a soccer game and kidnaps all 30,000 spectators as hostages. Then Black Dia announces that he will be killed if Giant Robo takes action. Daisaku puts a small radio in Over's car to locate their headquarters. Over finds it and is exasperated. He tells them that he will have Sparky destroy the whole city of Tokyo unless the Japanese Government surrenders unconditionally by next day's noon.
