AD rescues Carrie, the titular girl in the woods, who helped unleash The Brute. Seven years later, adult Carrie thinks back on life with AD and the fateful day the Brute got loose. AD trains Carrie to defend herself against The Brute and reminds her never to open the Door. When she's ready, he gives her a new arm that he has constructed out of metal, with a special blade made of material mined from the ground near the Door. With this blade, Carrie can defend herself against any of the creatures that come from the “wound” behind the door, including The Brute. (thetvdb.com)