Underneath a bustling human city lies another city, inhabited by monsters. The hub of the monsters' society is the famous Monster Academy, where young monsters go to be taught how to best scare humans out of their wits. But a human architecht designs a new sewer system which threatens to destroy the monsters' whole world. Students Ickis, Oblina, and Krumm must find a way to stop the humans' plan before it is too late.

The film is entirely live-action save for the monsters, which are rendered in Computer Generated Imagery. The music is a combination of current popular music and that of the original cartoon show. The film runs about one and a half hours.