Plot
In Bucharest, 2004 Father Dumitru and several nuns perform a violent exorcism on Sister Adelina Marinescu, who is believed to be possessed by the demon Agares. Dumitru and four nuns are arrested for murder when the three-day ordeal culminates in the death of Adelina.
New York journalist Nicole Rawlins convinces her editor to let her investigate the case. He cautions Nicole to not allow her personal views on faith or the death of her mother to affect her objectivity.
Nicole begins by interviewing Father Dumitru in jail. Dumitru claims he could have saved Adelina, and she only died because Bishop Gornick interfered with the unauthorized rite's completion.
At Adelina's funeral, Nicole meets Adelina's close friend Sister Vaduva, who insists the young nun wasn't murdered. Nicole follows a secret passage into the underground chamber where the exorcism was performed, and takes pictures of the cross where Adelina died before Bishop Gornick throws her out.
She then meets local priest Father Anton, who identifies Sister Vaduva as well as Adelina's brother Stefan Marinescu, whom Vaduva lives with on a nearby farm. Anton directs Nicole to speak directly to Bishop Gornick at St. Joseph's Cathedral.
Bishop Gornick tells Nicole that Adelina was mentally ill, not possessed, then goes on to infer that Father Dumitru was a rogue priest who overzealously performed an inordinate amount of exorcisms. She then has a strange encounter with mute gypsy boy, Tavian Amanar, outside.
Nicole returns to Father Anton. Anton theorizes that the demon allowed Adelina to die because it no longer needed her and could transfer its evil into someone else for another possession.
Nicole begins having terrible nightmares as well as waking visions involving strange activity. Vaduva again tells Nicole that the demon killed Adelina. Vaduva recounts how the seeming suicide of Father Gabrielle, a close mentor who unexpectedly threw himself from the monastery's bell tower, triggered Adelina's transformation.
Over dinner with Father Anton, Nicole confides in him how she lost her faith when her terminally ill mother died following a decision to abandon medical treatment for trust in God. Anton warns that Nicole is an easy target for the demon.
Nicole has another odd encounter with Tavian on her way back to the hotel. Following a sexual fantasy involving Father Anton, Nicole wakes to a frightening vision of Adelina.
Another visit with Vaduva reveals that Adelina fell in love with a man who led her away from the church, but the relationship ended unexpectedly. Adelina's plea for God's forgiveness seemingly invited The Devil instead. Vaduva describes what Adelina's exorcism was like.
Father Anton brings a bottle of wine to Nicole at her hotel as an apology for how he left things the night before. They drink together and Nicole dreams of sex with Anton once again, but the priest leaves without incident when Nicole falls asleep after drinking one glass.
Nicole interviews Dr. Funar, who diagnosed Adelina as a schizophrenic. Dr. Funar recalls a demonic vision Adelina had during her diagnosis. While driving, Nicole notices rays of sunlight, which her mother once said were signs from God, seemingly directing her to a cemetery. Nicole finds Father Gabrielle's grave, and learns he died on the same day as her mother.
Connecting that the demon possessed Adelina after it killed Father Gabrielle, Nicole rushes to the monastery. Gabrielle's records show that his last appointment was with Tavian Amanar.
Presuming that Father Gabrielle performed an exorcism on Tavian, Nicole goes to see the boy's father. Mr. Amanar reveals that Tavian actually retrieved Gabrielle to exorcise his father, as Mr. Amanar was hearing voices telling him to kill Tavian. Nicole is suddenly possessed by Agares and Father Anton races to the farmhouse to find Nicole violently possessed and levitating. While Tavian and Mr. Amanar hold her down, Anton performs an exorcism, pleading for Nicole to renew her faith. Nicole has a vision of her mother as the demon is ultimately expelled from her body.
Nicole returns to New York. End title cards reveal that Father Dumitru and the nuns were arrested and served seven years in prison for Sister Adelina's murder, and that Father Dumitru resumed his exorcism service after his release from prison.
