In a small rural town in Georgia, the abandoned Blackthorn farmhouse has stood untouched for decades. Locals whisper that it's cursed, the site of a brutal mass murder in 1966 when cultists tried to summon something from beyond—and succeeded. Since then, no one who's entered has come back unchanged.

When investigative journalist Clara Monroe stumbles upon a set of hidden journals marked with the number 666, she becomes obsessed with uncovering the truth behind the murders. Each entry details rituals, sacrifices, and something darker—the birth of a "child of ash" meant to be a vessel for a demon.

Clara convinces a small team of paranormal researchers to spend a weekend inside the farmhouse. At first, they encounter the usual—cold spots, flickering lights, whispers in the dark. But soon, the torment escalates. Doors slam shut on their own. Shadows crawl across the walls like living things. The sound of crying children echoes through the halls, though the house has been empty for years.

As night deepens, they realize the farmhouse isn't just haunted—it's alive, feeding off their fear. The journals begin to rewrite themselves in blood, revealing horrifying prophecies tied to each of the team members. One by one, they're targeted by the unseen force, lured into visions of their worst sins and deepest regrets, until the lines between reality and nightmare blur.

The team uncovers the truth: the cult never failed in 1966. They succeeded. The entity they brought forth still dwells inside the house, waiting for the sixth victim, the final sacrifice to complete its resurrection. Clara must confront the demon and her own family's dark connection to the house, for the journals suggest she was always meant to return—she is the vessel's bloodline.

The number 666 is not just the mark of the beast—it's the countdown. Once it reaches zero, Hell itself will be unleashed.