1426, Joseon (Korea). Hwani's family has never been the same since she and her younger sister went missing and were later found unconscious in the forest near a gruesome crime scene. Years later, Detective Min—Hwani's father—learns that thirteen girls have recently disappeared from the same forest that nearly stole his daughters. He travels to their hometown on the island of Jeju to investigate... only to vanish as well. Determined to find her father and solve the case that tore their family apart, Hwani returns home to pick up the trail. As she digs into the secrets of the small village—and collides with her now estranged sister, Maewol—Hwani comes to realize that the answer could lie within her own buried memories of what happened in the forest all those years ago.