Mysterious portals begin appearing in different locations in Equestria, allowing giant monsters from another world to enter and roam the land. Including the King of the Monsters: Godzilla.

Through unusual circumstances, the Mane Six and the Mane Five meet each other and band together to face down a hopeless future.

Godzilla and King Ghidorah are transported to the land of Equestria after being struck by the Oxygen Destroyer missile.

The Gargantuas, Sanda and Gaira, appear in the world of Equestria Girls, and must team up with the Mane Seven to stop a common enemy.