Three years into her marriage, the protagonist's mother-in-law suddenly passes away. Worried about his father living alone, her husband suggests they all live together. From that moment on, an unsettling atmosphere creeps into her life—she feels constantly watched, and her underwear starts disappearing. One day, her supposedly frail father-in-law violently rapes her, revealing his true, insatiable sexual desires. After that incident, she is forced to sexually serve her father-in-law whenever her husband is away. Trapped in a disturbing and anxious daily existence, she is gradually drawn into the horrifying reality of her father-in-law's true nature.