Bo Young is a young woman who is in desperate need of money. She answers an ad for a caregiver job and meets with Mother Kim, who is the only living relative of the wealthy grandmother Wang. Mother Kim hires Bo Young and sets strict rules for her to follow while taking care of Wang.
Bo Young quickly realizes that something is not right in the mansion. Strange and unsettling events occur, and Bo Young begins to suspect that Wang's death was not natural. She starts to investigate the mysterious deaths that have occurred in the area surrounding the mansion and discovers that foreigners who have visited the reservoir next to the mansion have suffered from a strange illness that eventually leads to death.
Bo Young becomes increasingly frightened as she learns more about the dark secrets of the mansion and the reservoir. She tries to leave but is stopped by Mother Kim, who reveals a shocking truth about Wang's death and the reason for her strict rules.
As Bo Young continues to investigate, she discovers a sinister plot and realizes that her own life is in danger. She must find a way to escape the mansion and expose the truth before it's too late. The film is a suspenseful thriller that keeps viewers on the edge of their seats until the very end.
