The fifth chapter of the Hellraiser series of films (Hellraiser: Inferno) was the first of them to go straight to DVD. Directed by Scott Derrickson, Hellraiser: Inferno tells the story of Joseph Thorne, a metropolitan Denver police detective with a dark side who encounters the literally diabolical cube of Lemarchandat while investigating the scene of a brutal and ritualistic murder. Detective Thorne very much likes puzzles, and is unable to resist picking up the puzzle box, and taking it home with him.
Solving the puzzle box brings about horrifying hallucinations for Thorne, but the experiences give him certain insights into the identity of the murderer who he now believes to go by the moniker 'The Engineer'. Searching for the Engineer plunges the detective into still another level of personal torment, and while relating his troubles to his psychiatrist, his doctor suddenly reveals himself to be 'Pinhead' - the titular character of the full Hellraiser series!
Pinhead is of course the leader a group of daemons (the Cenobites) whose pet bait is the infamous cube that is used to compel ordinary people to fiddle with and causing a portal connecting the everyday world to that of the Cenobite's to open. Pinhead proceeds to inform Thorne that he has in fact fallen into the realm of the Cenobites even as he was opening the box, and for him what ensues is the revisiting of his life through visions, highlighting all of his misdeeds. The aftermath of his cruelty is made painfully clear to him. The entirety of the experience amounts to nothing so much as a spell of psychological torture for Thorne, and indeed, the Engineer he was chasing turns out to be just a manifestation of his own evil deeds reflected back upon.
As for any sort of happy ending, no viewer of this film need not look for one. As is often the case in the Hellraiser saga victims receive retribution in the form of having their flesh impaled on hooks connected to metal chains that entrap them forever more.