This movie is also known as "The Exorcist III" or "William Peter Blatty's Exorcist III".
Do you dare walk these steps again? The spirit of an evil killer has been given the body of the priest that saved the girl in "The Exorcist". He is going to take revenge for the last exorcism.
A serial killer haunts the streets of Georgetown, do these events have anything to do with the exorcism of 15 years ago?
Ignoring Exorcist II: The Heretic, this one deals with a serial killer who was executed the same night of the exorcism in the first film with the girl Regan. The priest who fell down the flight of steps was been taken into the spirit of the killer to claim victim after victim some 20 years later. The killer mutilates priests and doctors and uses old women as a suspect. After the returning police detective Kinderman sees that it is the same serial killings of the Gemini Killer, he and another priest (Father Morning) decide to find and destroy the killer's spirit with using the final exorcism. But this exorcism will be much dangerous...