Had things worked out differently, Anguirus could have enjoyed a much more prominent presence in Godzilla's universe.

Aliens from space plan to conquer the world using space monsters Gigan and King Ghidrah ... can stop them is the combined efforts of Godzilla and Anguirus.

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.