Inspired by true events this supernatural thriller follows a seminary student (Colin O'Donoghue) sent to study exorcism at the Vatican in spite of his own doubts about the controversial practice and even his own faith. Only when sent to apprentice with legendary Father Lucas (Anthony Hopkins) who has performed thousand of exorcisms does his armor of skepticism begin to fall. Drawn into a troubling case that transcends even Father Lucas's skill the young seminarian glimpses a phenomenon science can't explain or control - and an evil so violent and terrifying that it forces him to question everything he believes.