The story follows Sun-yi, a teenage girl sent to the countryside to recover from a lung illness. Living a quiet life with her family, she discovers a feral young man hiding in the barn. He has no social skills, cannot read or write, and behaves more like a wild animal than a human. Sun-yi names him Chul-soo and begins the patient process of domesticating him, teaching him to wait for food, eat with utensils, and behave. As they bond, a tender romance blossoms, but the threat of the outside world and Chul-soo's animalistic nature soon puts their relationship in danger.