In a small mountain village in medieval Europe, ruled by a heretic noble, a fifteen-year-old nun named Mary has been raised by the church with no memory of her parents or her childhood. As her sixteenth birthday approaches, her nights fill with disturbing dreams — memories of someone who is and is not herself, doing something frightening. On a full moon night, the noble Gerald descends from his castle and requests that Mary be given to him in marriage on the day she turns sixteen. From that point, the village begins to change.