53-year-old Chieko begins developing an interest in her son's crotch, leading to an unusual scenario. When her son becomes frustrated from being unable to masturbate, he starts playing pranks on Chieko, but she doesn't merely respond in kind. Their relationship gradually deepens, transcending the boundaries of mother and son, evolving into something entirely new. Crossing forbidden lines, this taboo relationship unfolds with intense emotions and tension, creating a compelling drama.