The movie revolves around the wealthy Park family, who hire a new housemaid, Il-rang (played by Cho Yeo-jeong), to take care of their home and their young daughter. The family consists of father Keun-woo (played by Lee Jung-jae), mother Hye-yeon (played by Kim Do-yeon), and their daughter. As Il-rang settles into her new role, strange events begin to occur, and the family's seemingly perfect facade starts to crumble.