In the Mojave Desert in 1982, a man named William Nix, also calling himself “The Puritan,” Daniel von Bargen has gathered a devoted cult in an old house. Nix wields real magic and lays plans for a girl sacrifice, telling his followers he will save the world and grant them wisdom. A group of former cult members arrives to stop him, led by Caspar Quaid, Joseph Latimore, and Butterfield, Barry Del Sherman. The confrontation ends with Butterfield escaping, and Nix’s power seemingly unchecked until a girl shocks him through the heart with Swann’s gun, enabling the renegade cultists to overtake him. In a grim resolve, Swann binds Nix with an iron mask to crush his powers and they lay him to rest in an unmarked grave.
Thirteen years later, New York City is abuzz with occult intrigue as Harry D’Amour, Scott Bakula, an occult-focused private detective, wrestles with the aftereffects of an exorcism. He flies to Los Angeles to chase a routine insurance-fraud lead, only to stumble upon Quaid, now a fortune teller, who is violently attacked by Butterfield and Ray Miller, a man of prodigious strength. Quaid dies in the street, but not before reading D’Amour’s palm and warning that the Puritan is coming, sealing his fate with a prophetic breath.
Philip Swann, a once-humble man who has become a famous stage illusionist, now lives in a Beverly Hills mansion with his wife Dorothea, Famke Janssen. Philip believes Quaid was killed by Nix’s loyalists, and Dorothea enlists D’Amour’s help to guard her husband. D’Amour agrees to step in, conditional on protecting Philip if Quaid’s killers resume their hunt. Dorothea invites him to watch Philip’s next magic show, where a new illusion collapses and Philip is murdered onstage, stabbed by a cascade of swords. Backstage, D’Amour fights Butterfield and Miller, killing Miller in self-defense as Butterfield escapes. The next stop is the famed Magic Castle, where D’Amour gains access to the Repository, a room said to house every secret of magic. There he discovers that Philip’s “illusions” were powered by real magic learned from Nix.
Dorothea reveals a hidden layer of the past: she was the girl Nix kidnapped years earlier, saved by Philip, and married out of gratitude and obligation. The lovers’ bond complicates the investigation as D’Amour and Dorothea awaken to a surprising truth—Philip faked his own death to shield both of them from Nix and his retribution. With Valentin, Philip’s loyal assistant, explaining the ruse, D’Amour agrees to keep the deception alive so they can withstand Nix’s looming return. At Philip’s funeral, D’Amour tailors his suspicions toward a mysterious pallbearer who turns out to be Philip himself, masquerading as an illusionist to remain wealthy and protected. The plan shifts toward alliance; together, they vow to confront Nix if he’s ever resurrected.
Butterfield, seeking Nix’s dead body, tortures Valentin for its location and abducts Dorothea. He finally uncovers Nix’s corpse and brings it back to the desert house, where Nix’s loyalists—who had waited in silence—remove the iron bindings and resurrect him. The once-decayed figure returns, now monstrous, promising knowledge and power to those who bow to him. Acting on information given by the dying Valentin, Swann and D’Amour rush to the scene. Nix conjures a cataclysmic deep chasm that swallows the cultists, declaring that only Swann is worthy of his knowledge.
Dorothea is hurled into the chasm, but D’Amour rescues her and kills Butterfield in the wake of the chaos. Nix confesses that his true aim was not salvation but annihilation, and he extends an offer to Philip to join in the destruction—an offer Philip accepts with reluctance, though he still cares for Dorothea. jealousy flares as Nix assaults Philip with magic, seemingly ending the illusionist’s life. Dorothea seizes D’Amour’s gun and fires at Nix, striking him in his mystical third eye. He retorts that she should not have taken Philip away, for they were meant to be together after humanity’s doom.
Philip uses his last reserves of life energy and magic to help D’Amour land a final blow against Nix, then dies from his wounds. Nix tumbles to the bottom of the chasm and sinks into molten rock, a grim finale tempered by a somber moment between Dorothea and D’Amour as they sense something rising from the fissure. They flee the room as Nix, burning in the pit, unleashes one last spell, disintegrating Philip’s body to bones and sealing the chasm once more. Dorothea and D’Amour escape the house and walk away into the desert together, their bond forged in fire and magic as a new, uncertain dawn approaches.
