Four odd-ball scientists get kicked out of their cushy positions at a university in Manhellton where they studied the occult. They decide to set up shop in an old firehouse and become Ghoulbusters, trapping pesky ghosts, spirits, haunts, and poltergeists for money. They wise-crack their way through the city, and stumble upon a gateway to another dimension, one which will release untold evil upon the city. The Ghoulbusters are called on to save the Bad Apple.