On October 8th, 2009, a chilling tragedy struck Hell House, a haunted house attraction in Abaddon, Upstate New York, where 15 people—nearly all of the staff—died in what authorities declared a “severe malfunction.” A documentary crew chasing answers dives into the case, led by producer Diane Graves, and soon they begin to hear whispers of something beyond ordinary misfortune. They track down the sole surviving Hell House staff member, Sara Havel, Ryan Jennifer Jones, who offers the team uncut, behind-the-scenes footage that shows what happened up to the tragedy.
Sara’s tapes follow the company’s arrival at the dilapidated Hotel Abaddon in Rockland County, New York as they set up for Halloween. The plan centers on a basement finale in which an actress is chained up, supposedly to be sacrificed to a cult. The crew hires several local scare actors, including Lauren A. Kennedy as Melissa, who tells Alex and cameraman Paul O'Keefe that the hotel is haunted. With the help of expert interviews, the team gains context about the site’s dark history. The Hotel Abaddon was originally built by the enigmatic cultist Andrew Tully, who chose the location because the town’s name—Abaddon— echoes a demon guarding the gateway to hell. In 1989, two guests disappeared—the mother and her 11-year-old daughter—and although Tully was cleared of their disappearance, the hotel’s reputation spiraled, and he hanged himself shortly afterward.
As Hell House goes up, the crew begins recording undeniable supernatural phenomena—an autonomous clown mannequin, shadowy figures that flicker in and out of view during strobe tests, and even moments where Paul and Sara appear to be possessed. Yet Alex remains resolute, determined to open on schedule despite the growing unease. The haunting intensifies: Paul contemplates quitting, but his loyalty to Alex keeps him in place. That night, Paul vanishes after a frightening encounter with a ghost girl, and the following day the crew discovers him in the basement, withdrawn and unresponsive.
Tensions rise as Tony, the staff technician, quits after Alex’s increasingly unhinged push to press forward. Mack persuades him to stay for the sake of finishing the project, but the pressure ultimately proves too much. Hell House finally opens to a large crowd, but the truth behind the tragedy begins to unravel before the audience’s eyes. In the basement scene, Melissa is brutally killed by a shadowy ghost cultist, triggering a panicked stampede among the guests. Tony is slain while attempting to protect Melissa, and Mack and Sara escape to the attic, where they find Alex hanged. Sara escapes as Mack is surrounded and killed by shadowy cultists, and the footage from 2009 is abruptly cut short.
In the present, Sara asks for a break from the interview, hinting that she will be awaiting them in her hotel room, 2C. She then suggests the crew enter the Abaddon Hotel to witness the crime scene firsthand. Diane and her cameraman head to the hotel, while Mitchell remains behind to catalog Sara’s footage. He uncovers footage showing that after Mack’s death, a possessed Paul slaughters Sara before cutting his own throat. Diane and her companion break in, ignoring Mitchell’s calls, and confront the aftermath on the second floor. They discover a room labeled “2C” and find Sara sitting with her back to them. They try to flee, but are suddenly attacked by a ghoulish Sara and two shadow cultists, bringing the documentary’s discoveries to a dramatic, chilling close.
