When Tom (Ben Barnes) was about to turn 13, his father asked the local exorcist Spock to accept him as his apprentice. Exorcist is a dangerous profession full of thrills, horrors and excitement that specializes in fighting alien monsters, witches and various evil spirits. It requires courage, bravery, wisdom, dedication and social responsibility. After experiencing the test of terror, Tom was finally accepted as an apprentice by Spock. But because Tom agreed to the plea of the beautiful girl Alice (Alicia Vikander), he mistakenly let go of the witch Malkin who was imprisoned in the dungeon by Spock. As soon as Malkin ran out of the dungeon, he launched a crazy revenge campaign, and crises, terror and blood were lurking everywhere. In order to prevent the crime from happening, Tom risked his life and began to hunt down the witch. A battle between justice and evil begins.