After losing her husband, mother Hitomi lives alone with her son Kō. Once bright and cheerful, she now suffers daily as her son's obedient sex slave within the confines of their home. Unable to endure the constant humiliation and sexual abuse inflicted by her son at all hours, Hitomi confides in her son's homeroom teacher, Yamashita. However, Yamashita reveals he already knows about his relationship with Kō—and suddenly begins touching Hitomi's body, disclosing that everything was orchestrated by her son. Feeling immediate danger, Hitomi tries to flee—but she cannot escape.