An experimental satellite-based weapon that fires miniature black holes, called the Dimension Tide, opens a wormhole through which a giant prehistoric dragonfly enters the present and deposits a single egg before exiting through the wormhole. A boy finds the egg and takes it with him when he moves to Tokyo. The egg starts oozing a strange liquid, so the boy throws the egg in the sewer. The egg, actually a mass of hundreds of eggs, splits up and starts growing when exposed to water, hatching into giant dragonfly larva called Meganulon that come out of the sewer to feed. They flood a portion of the city and moult on the sides of buildings, becoming adult Meganula.
Suddenly, monsters all appear around the world at major cities and the EDF promptly swings into action, attempting to drive away the monsters, but achieves little success. Then, after destroying much of their cities, the monsters vanish as an enormous alien mothership hovers over Tokyo. Aliens called the Xiliens then reveal themselves, insisting they are friendly and that they have eliminated the monsters. They also warn the Earth’s governments about impending danger in the form of a planet called Gorath that will crash into Earth.
Gamera is a giant, flying turtle from a popular series of kaiju (Japanese giant monster) films produced by Daiei Motion Picture Company in Japan. Created in 1965 to rival the success of Toho Studios Godzilla during the daikaiju boom of the mid-to-late 1960s, Gamera has gained fame and notoriety as a Japanese icon in his own right