After Godzilla emerged from Mount Fuji and wreaked havoc across the countryside and broke Anguirus' jaw, it appeared he had returned to his villainous ways. When Godzilla reached Tokyo and began destroying it, another Godzilla appeared from underneath a building. This second Godzilla fired his atomic breath at the other one, revealing it as a robotic impostor. The robot, Mechagodzilla, burned off the rest of its disguise and revealed its full arsenal of weapons. Godzilla fired his atomic breath at Mechagodzilla, which countered with its eye-mounted laser beams. The monsters' beams locked and exploded, sending Godzilla crashing intoTokyo Bay, with his blood welling to the surface. Mechagodzilla was damaged as well, and returned to the base of his alien masters, the Black Hole Planet 3 Aliens, in Okinawa.