In a household consisting of a sister, her younger brother, and their parents, the brother becomes a shut-in after being bullied at his part-time job. The tense atmosphere at home worsens when he begins to sense a change in his sister Mao. His gaze gradually turns into sexual desire, and he starts pressuring her as if threatening her. Torn by conflicting emotions, Mao finds herself unable to resist, and their family dynamics grow increasingly distorted. The parents, though aware of what's happening, choose to ignore it, leaving Mao feeling isolated. As the days of being impregnated by her brother continue, how much longer can she endure? A delicate and shocking story depicting the dark side of family life.