Monster Zero

People from Earth have discovered a new satellite hidden in the shadow of Jupiter that they name "Planet X". In order to verify if it is inhabited, astronauts Glenn and Fuji are sent on an expedition on board an interplanetary rocket. When they arrive on the planet, they are captured by its people who live underground to protect themselves from the terrible destruction sown by the monster zero, best known on Earth as "Kingugidora", a three headed monster that ravages all in its path. Residents of the planet X make a proposal to the two astronauts : In exchange of a cure against cancer, they ask them to help bring monsters 01 and 02, respectively Godzilla and Rodan, to planet X from the Earth in order to rid the small satellite of Kingugidora...