Workers on the underground Tokyo Geo-City Project uncover a series of limestone caverns. However, one of the workers is a member of the Earth Defense Army, militant anti-Project Babylon terrorist group. He has set off a bomb and threatens to set off more in an aim to destroy the project. The SV2 are called in to help. Noa along with Kanuka who has anti-terrorist and bomb disposal training, set off in their Labors to defuse the bombs and apprehend the criminal. While searching for the bombs they come across a large creature in the water which attacks them...