After being institutionalized in a mental hospital, Korean teen Su-mi (Yeom Jeong-ah) reunites with her beloved sister, Su-yeon (Su-jeong Lim), and they return to live at their country home. The girls’ widower father (Mun Geun-yeong) has remarried, and the siblings are immediately resentful of his new wife, Eun-joo (Kap-su Kim). As Su-mi and Su-yeon try to resume their regular lives, strange events plague the house, leading to surprising revelations and a shocking conclusion.