Fuji was an astronaut headed to the newly discovered Planet X. When he and his partner land, Fuji sets out to plant some flags on the planet's surface but when he returns to the landing site he finds that his partner and their ship have vanished. He is then contacted by the Controller of Planet X and is made to enter the Xiliens' underground city. He is led to his partner Glenn and they are formally introduced to the Controller, who makes them an offer. The Xilien planet was terrorized by a kaiju called Monster Zero. The Xiliens offer the Astronauts a drug to cure all diseases in exchange for Godzilla and Rodan. The Astronauts inform their superiors of the trade offer, and plans are put into motion. Meanwhile, Fuji's sister Haruno has been dating an inventor whom Fuji disproves of, and Fuji learns that while he was away, The man had made 100,000 dollars from selling an invention, and becomes indignant about his disapproval. Eventually, Glenn tells Fuji that he saw the Controller on earth, a claim that Fuji initially scoffs at, but is later proven to be true. Fuji eventually is chosen to return to Planet X with Glenn and the leader of the World Space Authority. When they return to earth with the tape, they play it and learn that it holds, not a formula, but a declaration of dominance over earth. Fuji eventually finds that the Xilien UFOs have the monsters under control with magnetic waves, and he begins to develop a beam to disrupt the signals. they are eventually put to use alongside sounds that are found to immobilize Xiliens, and the alien horde is defeated.