With New York being plagued by power outages, the Ghostbusters set about to capture Killerwatt, a ghost who has the ability to possess electrical devices. But things take a turn for the worse when Killerwatt takes control of the city's power grid.

Slimer leaves home after Peter yells at him for eating Winston's birthday cake, and the Ghostbusters set out to find him. But more problems arise when Egon discovers a poltergeist feeding off the power of ghosts in the local area; who only needs one more ghost to reach his full power.