It is Halloween night in Haddonfield, Illinois. Six gunshots pierce the silence of this normally quiet town. Neighborhood kids trick-or-treating on the street stare as a man plunges off a balcony. A doctor form the county mental hospital rushes from the house. He has followed his patient, who escaped from the institution, back to Haddonfield, where fifteen years earlier he brutally murdered his own sister. The demented young man has already killed three teenagers this evening. Tonight's massacre has only begun!