The Ghostbusters experience some down time, and Egon and Janine decide to take advantage by having a stroll through Central Park. They eventually wind up at the estate her cousin Michele had just inherited and learn that the place is haunted. They meet a ghost named Aaron whose mother was possessed by the spirit of the evil witch Ginerva and ritually killed him. With Ginervaís host body dead, her essence lies in the hat that Michele had found and put on! With Ginerva in Micheleís body, Alecís life is in danger unless Egon and Janine can stop her.