Third installment of the "Gakko No Kaidan" series follows the trek of several elementary school students as they wander into an alternate world that exists on the opposite side of a school mirror. Nishida Naomi (the hapless teacher in "Gakko No Kaidan 2") returns as the teacher who accompanies the children on their journey into the surreal universe.
A young girl wanders into a wing of her elementary school that has been abandoned for years and is rumored to be haunted. When she doesn't come back, a group of her classmates go looking for her, only to find that they, too, are trapped inside. They must somehow find their way to safety, and quickly, because the rumors of ghosts are turning out to be true.
Mothra's dark counterpart, Battra, emerges to eliminate humanity on behalf of the Earth. Two tiny fairies called the Cosmos offer their help by calling Mothra to battle the creature. Unfortunately a meteorite has awoken a hibernating Godzilla as a three way battle for the Earth begins.
