The revelation of his own former humanity in Hellraiser II causes Pinhead, a demon called a Cenobite, to be split into two entities: his former self, World War I British Army Captain Elliot Spencer, and a manifestation of Spencer's id, which takes on the form of Pinhead. While Spencer ends up in limbo, Pinhead is trapped, along with the puzzle box, among the writhing figures and distorted faces etched into the surface of an intricately carved pillar � the Pillar of Souls.
J. P. Monroe, the womanizing owner of a popular nightclub called The Boiler Room, buys the pillar. An ambitious young television reporter, Joey Summerskill, sees hooked chains embedded in a teenage clubgoer in a hospital emergency room. They come to life and tear the clubgoer to pieces. A young homeless woman, Terri, who came in with the clubgoer explains that the chains sprang from the puzzle box, which she pried from the pillar. Terri gives the puzzle box to Joey. While investigating the box's background with the help of her cameraman, "Doc", Joey invites Terri to stay with her. Joey uncovers a video tape from one of Pinhead's former victims, Kirsty Cotton, that explains the puzzle box is the only means of returning Pinhead to Hell. Pinhead remains dormant until Monroe has sex with a clubgoer, Sandy. Hooked chains drag Sandy to the pillar, and Pinhead absorbs her body. Pinhead points out that they have both used Sandy for their own purposes. Although initially horrified, Monroe agrees to bring Pinhead more club members so he can feed on them and be freed. In return, Pinhead promises Monroe power and unnatural delights.
Joey has recurring nightmares about how she presumes her father died in Vietnam. During one such dream, Spencer contacts Joey. He explains that his experiences in WWI caused him to lose faith in humanity, and he sought out the forbidden pleasures promised by the puzzle box. Spencer tells her that without his humanity to act as a balancing influence, Pinhead is completely evil and will indiscriminately wreak havoc on Earth for his own pleasure, in violation of the Cenobite's laws. To defeat him, Joey must reunite Spencer's spirit with Pinhead and use the puzzle box to return him to Hell. A misunderstanding leads Terri to believe that Joey has abandoned her, and she returns to the arms of her ex-boyfriend, Monroe. Monroe attempts to feed her to Pinhead, but she overpowers him. Before she can flee, Pinhead talks her into feeding Monroe to him, promising to turn her into a demon in return. Now free, Pinhead massacres the club's patrons. Hearing the news reports, Joey goes to the club to investigate.
