On the night of his sixteenth birthday in 1993, James and his closest friends decide to end the celebration with what they believe is nothing more than an innocent thrill—a séance inspired by one of his father's old stories. What begins as laughter, underage drinking, and teenage curiosity quickly turns into terror when an unseen presence answers their call. Moments later, James is overtaken by something none of them can explain, leaving his friends haunted by what they witnessed but unable to convince anyone it was real.

As the weeks pass, James begins to change. Violent mood swings, disturbing voices, an overwhelming hatred of anything sacred, and terrifying supernatural events consume his life. His once-loving home becomes a place of fear as unexplained phenomena escalate into horrifying acts of self-mutilation, impossible physical feats, and unmistakable signs of demonic possession. Desperate to save his son, James's father turns to Father Ambrosi, a seasoned Catholic priest who recognizes the evil for what it is and risks everything to confront it.