Godzilla vs. Megalon

Astronauts Glenn and Fuji investigate Planet X and encounter mysterious aliens known as the Xiliens, who ask Earth's people to help save their world from "Monster Zero". In exchange for borrowing Godzilla and Rodan, the Xiliens offer a cure for cancer. As Glenn investigates, he develops a romance with Miss Namikawa and uncovers the Xilien's true intentions.

In an alternate timeline the original Godzilla is never defeated and repeatedly reemerges to feed on Japan's energy sources. A new inter-dimensional weapon called the Dimension Tide is created with the intent of eliminating Godzilla. However, the new weapon might also serve as a gateway to something far more sinister.

An independent group of researchers called the Godzilla Prediction Network (GPN) actively track Godzilla as he makes landfall in Nemuro. Matters are further complicated when a giant meteor is discovered in the Ibaragi Prefecture. The mysterious rock begins to levitate as it's true intentions for the world and Godzilla are revealed.

War reduced Japan to zero, and Godzilla plunged it into minus. Two years have passed since then, and the country has faced agonizing struggles to achieve recovery and finally reclaim its daily life. Just as humanity managed to cling to a hard-won peace, a new threat strikes, crushing hope in an instant. There is no third time. Everything ends here.

An Okinawan prophecy that foretells the destruction of the Earth is seeming fulfilled when Godzilla emerges to return to his destructive roots. But not all is what it seems after Godzilla breaks his ally Anguirus's jaw. Matters are further complicated when a second Godzilla emerges, revealing the doppelgänger as a mechanical weapon.