A newly opened ghostly-themed amusement park prompts Prime Evil to send Apparitia and Bratarat to haunt it. When the Ghostbusters realize that the ghosts are loose in the park they fight back, but they must first find Jessica's mischievous nephew Corky.

The Ghostbusters travel to the future to help Futura save her nephew, Laser and his friends Rae and Tempo who have been captured by Corpulon, a large slug-like energy ghost who seeks vengeance against Futura.