Hokum

Ohm Bauman is an American author struggling to finish the conclusion of his successful 'Conquistador' trilogy. After glimpsing the ghost of his mother at home, Ohm decides to visit The Bilberry Woods Hotel in rural Ireland, where his parents had honeymooned, to lay their ashes to rest. The hotel staff includes owner Cob, his son-in-law and front desk clerk Mal, groundskeeper Fergal, bartender Fiona, and bellhop Alby. Ohm overhears Cob tell two children the story of the Cailleach, a local witch who kidnaps children and leads them in chains on a tour through the underworld, where they are clawed at by the souls who live there. Ohm is abrasive and dismissive toward the staff, but warms to Fiona after she identifies the location of a photo his mother took. While spreading his parents' ashes, he meets and bonds with Jerry, a local living in his van who frequently consumes milk laced with magic mushrooms.

Fiona and Alby tell Ohm that the honeymoon suite is locked off and supposedly haunted by a witch that Cob had trapped inside. After belittling Alby's dreams of a writing career, Ohm returns to his room. Later, Fiona finds Ohm's tape recorder at the bar. While attempting to return the recorder, Fiona discovers that Ohm has hanged himself. Ohm awakens in a hospital, alive thanks to Fiona's intervention. When he returns to the hotel, Mal informs him that Fiona has been missing since the hotel's Halloween party and Jerry is the prime suspect for both Fiona's disappearance and the murder of his wife. Ohm confronts Jerry, who claims to have seen Fiona's ghost in the hotel directing him to the honeymoon suite. Ohm doesn't believe Jerry's story but agrees to check the suite with him. Jerry confesses to killing his wife, but says it was a mercy killing due to illness.

With the hotel closed for the season, Ohm and Jerry break in to investigate. Fergal knocks Jerry unconscious before driving him to the police. Ohm sneaks into the honeymoon suite, where he is haunted by supernatural visions of his mother and memories of shooting her dead by accident with his father's gun as a child. Mal arrives, pleading with Ohm that they must head back downstairs and out of the honeymoon suite, but Ohm inspects a dumbwaiter, discovering Fiona's corpse inside. Mal locks Ohm in the suite and flees the hotel. Ohm finds his tape recorder on Fiona and learns that Fiona was pregnant with Mal's baby; Mal drugged her and locked her in the suite to prevent his family finding out.

Jerry awakens in Fergal's van and escapes to the hotel. The hauntings intensify as Ohm struggles to find a way out. Spotting a fire escape on a map of the basement, Ohm descends via the dumbwaiter. He encounters the witch and fends her off with a protective circle of chalk. In the morning, Mal arrives at the hotel to dispose of Ohm and is surprised to find Jerry. Ohm manages to ring the suite bell, alerting Jerry to his presence. Mal starts a fire in the hotel to cover his tracks before shooting Jerry dead with Fergal's crossbow.

Ohm flees into the basement, pursued by Mal. Mal is confronted by the witch, who chains his hands and leads him to the underworld. Ohm makes peace with his mother's ghost and removes his own chains before escaping. As the hotel burns, Ohm is saved by Fergal after the latter hears Ohm’s mother’s ghost calling to him.

Alby visits Ohm in the hospital, telling him Fiona and Jerry's remains have been found but Mal is missing. Alby admits to vengefully spiking Ohm's whiskey with Jerry's mushroom powder. Ohm notices he still has bruises on his wrists consistent with being placed in chains, and recalls Jerry telling him that drugs allow people to open their mind to the supernatural. Ohm agrees to read Alby's manuscript, and writes a more hopeful ending to his 'Conquistador' trilogy.