After enduring the monsters rampage for too long, the humans decided it was the last straw after witnessing Godzilla's recent attack. The humans attempts to destroy Monster Island with a nuclear warhead in hopes of destroying all the monsters, but their actions only attracted the attention of the Vortak empire, who plans to invade the planet with an army of monsters. Can the humans and the monsters put aside their dispute and work together or will this be the end?

Natori Yoshida, a young man seeking vengeance for his father's death, meets with G-Force to discuss a weapon he is creating to finally kill Godzilla: The Oxygen Destroyer. Unbeknownst to them, Godzilla is on the verge of a meltdown, an event with cataclysmic results. To make matters worse, Spikesaurus, a monster as old as Godzilla, returns to wreck havoc on Japan. G-Force Captain Yukijiro Nakamura is forced to make a controversial decision: to not engage the monsters until G-Force has needed weapons. With Godzilla's temperature ever rising, Spikesaurus' resurgence, and the lack of necessary weapons, the fate of the world has never been more uncertain...