In hopes that fresh air will cure her chronic lung ailment, Soon Yi (Park Bo Young) is suddenly shuttled to the countryside, where she quickly discovers there's a lot to adjust to in their new house and surroundings — namely, a wild boy named Chul Soo (Song Joong Ki) who lives in the barn. Though initially believed to simply be an orphan lacking social skills, Chul Soo begins to develop feelings for Soon Yi, eventually leading to a love triangle that exposes the truth behind the werewolf boy.