After losing their academic posts, a team of parapsychologists (Dan Aykroyd, Bill Murray and Harold Ramis) goes into business as "ghostbusters" -- exterminators of ghouls, hobgoblins and supernatural pests of all stripes. An ad campaign pays off when a knockout cellist (Sigourney Weaver) hires the squad to purge her digs of demons. Turns out the place has become an entryway for a legion of fiendish spirits bent on terrorizing the Big Apple. …