Slimer is really starting to get on the Ghostbusters' nerves. So they confront him and Slimer flees to the attic. The Ghostbusters are summoned and in the mean time the Firehouse is attacked by a powerful ghost. Now it's up to Slimer to defend the headquarters.
The Ghostbusters are in Japan investigating the sighting of several immense creatures in Tokyo Bay. They encounter Kenji, who tells them that the creatures are the same ones to those in an old Japanese movie monster from the 60s.