Twenty-five years after Heaven's Veil, a documentary crew hunts for the truth behind the cult’s mass suicide. Maggie Price, a determined documentary filmmaker, and her brother Christian reach out to the sole survivor, Sarah Hope, who was five years old at the time of the tragedy, hoping she can reveal footage that has never been found. Christian explains that their father was the FBI agent who led the investigation and, after the case closed, he took his own life. This haunting family history pushes Maggie and Christian to push deeper into the mystery, seeking answers that might finally lay the past to rest.
The team travels to the remote site where Heaven’s Veil carried out its final acts, setting up camp and filming Sarah as she confronts memories and visions that threaten to overwhelm her. As night falls, she awakens from a nightmare to discover that Ed, the grip, has vanished with their van. Ann, the sound editor, and Nick, the gaffer, head out to find him while Maggie and the others follow Sarah to a secluded house hidden in the forest. Inside, they uncover the lost footage and the corpse of Karen Sweetzer, a missing member of the cult. A tape found near Karen’s body contains a brief, chilling address to Sarah before she dies.
Watching the found footage, the group learns that Jim Jacobs, the quasi-Christian occultist who led Heaven’s Veil, claimed to have unlocked a path to eternal life through alchemy. They also discover that Karen is Sarah’s mother, a revelation that adds a personal layer to the horror. Ann and Nick return with the grim report: Ed has died in a car accident. The tapes reveal Jim’s dangerous experiments with drugs intended to help him traverse into the spirit realm. In one trance, Jim appears to possess a cult member and declares that he has freed the first binding from her soul. Ghosts kill and possess Nick when he leaves to restart the house’s generator; he later reappears, returning to kill Ann when they are alone.
As the possession intensifies, the remaining filmmakers grow convinced that the house is truly haunted. Jill, the sound editor, and Matt, the cameraman, discover Ed alive but badly injured. Ed turns on Jill, killing her, and the group returns to the house with shaken resolve. Sarah conducts a seance to contact her mother, who urges her to persuade the others to stay. Ann murders Christian, who rises again to join the others, leaving Maggie and Sarah as the only two who remain unpossessed.
In the final reel, Jim reveals a grim plan: the poison administered to the cult members was meant to be countered by an antidote. Karen objects to poisoning the children and helps Sarah escape, but Jim is revealed to be Sarah’s father and forces Karen to take the poison. Karen dies with the footage, leaving the group vulnerable as the FBI arrives too late to interrupt the ceremony and deny the antidote. The cult members all perish. Sarah reveals that the ghosts of Heaven’s Veil have possessed the documentary team, and Jim, now possessing Ed, nails Maggie to a tree despite her protests that her father did not know about the antidote. The police arrive, bringing Matt, but they, too, are killed and possessed. With the ritual complete, Jim declares his intention to feed on the souls of the rest of the world, leaving the living to face a lingering, malevolent presence that stretches beyond the confines of the house.
