Maritime Self-Defense Force officer Mitsuru Akizuki is suddenly attacked by a mysterious submarine battleship equipped with new weapons, and the ship is sunk. He was badly wounded, but after a month he followed the submarine and put it out to sea again. Among them, Kentaro Akizuki, the younger brother of Misa Akizuki and the main character, meets Dr. Tenma, a genius robot scientist. And the battle between the Akizuki brothers and the Mafui gang, who are planning to conquer the world, begins.