A cataclysmic monster battle for all ages! As the Devonians move their plans into endgame and humanity meets them on the battlefield, Godzilla will be the monster that determines the fate of the planet! Will the new rulers of Earth bring about a reign of life... or death?
SPOILER WARNING: This section may contain major plot and/or ending details. Proceed at your own discretion.
The USS Simon and CKR are being attacked by several juvenile Destoroyahs. As Chavez leads Lucy and the Kaiju Investigation Team to one of the helicopters, he throws Steven Woods a gun which one of the Destoroyahs snatches away. Woods tries to use a pocket knife to attack it, but it only annoys the creature, which attacks him. Chavez fires a sonar gun at the attacking Destoroyah, causing it to fall on Woods. As another Destoroyah tries to attack Chavez, Lucy fires another sonar gun at it. Woods is shown to be okay, but injured. Meanwhile, Godzilla is still hanging on to Titanosaurus's leg as Manda bites Godzilla's arm. Godzilla responds by grabbing onto Manda's neck. The Devonian king is informed that their monsters along with Godzilla have arrived. As Godzilla, Titanosaurus, Manda, and Gezora are fighting, the ocean floor collapses, causing them to land in the Devonians' capital city. As the monsters are fighting, the Devonians enter the Cryog ship to escape. Back on the surface, the CKR team is defeating the Destoroyahs, but they retreat and transform into their perfect form. As Destoroyah is about to destroy the ship, Jet Jaguar pushes the ship out of the way. He briefly fights Destoroyah, but is injured when he is blasted by Destoroyah's micro-oxygen beam. Jet Jaguar then shrinks to his human size and activates Kiryu, using the Absolute Zero Cannon to freeze Destoroyah solid, seemingly killing him. The CKR team then task Jet Jaguar to stop submarines from launching nuclear warheads at Godzilla. Meanwhile, the underwater battle comes into an end as Godzilla manages to twist Titanosaurus's arm after he tried to punch him. Behind him, the Cryog ship tries to escape to the surface, but Godzilla stops it by blasting it with his atomic breath. The submarines fire the warheads at Godzilla as Manda and Titanosaurus retreat. Jet Jaguar tries to stop them, but he is too late and the explosions bury Godzilla. At the facility, the Devonian defector reveals to Allison that he was actually the Cryog leader Rhizon in disguise, who kills Allison and escapes. Chavez and the injured Woods are later seen in the hospital. Professor Ando offers Lucy a chance to stay on the Monster Islands, which she gladly accepts. At the bottom of the ocean, Godzilla's dorsal plates are shown poking through the debris that buried him underwater.