Godzilla is sleeping in the ocean, and the fission line reptures due to a metorite landing on the contienant of Asia.
Godzilla is awoken by the earthquake, swimming to japan. He destroys and feeds off of the closest power plant, which causes the military to try and shoot him down with the normal methods. But then, in America, A giant alien withsickla claws is destroying city after city, nothing stands a chance. Half way through the movie, godzilla defeats this unknown, and weak monster. The aliens from a planet beyond our solar system, come to claim thier "Run-away pet". They rebuild teh cities, and even offer to destroy godzilla, but in teh process of "Destroying" him, they take away most of his bodily radiation, and leave him to rot in a trench. He is helpless. The mutated alien monster apears, as gigan. It now has a beam, and it has sharper sickles, and a mechanical body. In a last ditch effort, the japanese adnd the U.S.A launch a nuclear bomb, hitting gigan. Gigan, is thrown into teh sea by the massive explosion, and retreats briefly to heal. But, without the guidence of his leaders, he swims over Godzilla, activating the dinosaur. Godzilla raises from the ocean,a nd grbas gigan. He destorys gigan on the mainland of asia. Godzilla proudly burns the rest of the mutants body, battle scared from sickle marks.
(The next, would probably be a Godzilla X Orga reboot and then have a godzilla X King Ghidrah. Then have one last epic fight, featuring mechagodzilla (Similar to Kiryu) and godzilla fighting Grand King Ghidorah)