Mayumi Tezuka, married into a strict household, lives under oppressive rules that go beyond societal norms. Among them is a special tradition that only women must uphold—her duty not only to raise her son but to fulfill her role as a woman. After her husband's death, she is repeatedly taken by her lustful father-in-law, day after day. Eventually, the time comes for her to pass on the family's female fate to her own son. In that moment, all her past suffering finally gains meaning.