The Hockomock is a swamp located in what is known as the Bridgewater Triangle in southeastern Massachusetts, an area of known paranormal activity. In the language of the Wampanoag nation, Hockomock translates to "the place where spirits dwell."

A paranormal team hires a local guide, Tom Bradford, to take them into the swamp where they will create a documentary proving that the tales are real. Spectral voices and orbs, apparitions known as Tei Pai Wankas, and lastly, the mythical Pukwudgies of Wampanoag lore, known to beguile and lure the unsuspecting to their deaths.

The team, encouraged by the orbs and spectral voices that they have already experienced on their trek inward, attempt the resurrection of the fabled Wampanoag death spirit, Hobbomock. When Tom Bradford returns after medically evacuating a psychic medium, Judy Brown, he finds all but one of the remaining team dead by decapitation. Randy Young, a videographer, is missing, along with the heads of the three victims.

With the resurgence of Hobbomock, violent crime and paranormal activity surges all over southeastern Massachusetts, and a serial axe murderer emerges in the nearby towns whose modus operandi matches the murders within the swamp. A task force is formed to solve the murders, which includes Tom Bradford and Judy Brown as consultants. Judy Brown, angry at the stubbornness of the police, resorts to channeling the dead wife of Detective Sergeant John Stroud to convince him of the necessity to believe in the paranormal and remove the evil of Hobbomock. Now Johnny Stroud, with Judy Brown, Tom Bradford, and an old Wampanoag shaman on one side, and the no-nonsense, logical minds of the task force team on the other, must find the balance between reality and the unexplained to stop the axe murders and halt the spread of Hobbomocks evil.