Yukie Kitazawa is a housewife and mother to two adopted daughters, Rumi and Tomoko Kitazawa. Her husband experiences impotence stemming from suppressed sexual attraction toward Tomoko, leaving Yukie in a state of deep emotional and physical deprivation that shapes her character.

This vulnerability intensifies when Yukie causes a traffic accident with Taketo Nogawa, the son of a powerful, corrupt business owner. Unable to pay the demanded settlement, she enters a coercive arrangement where Taketo exacts sexual acts as repayment. The situation escalates through blackmail orchestrated by Taketo and his father, forcibly drawing both Rumi and Tomoko into the exploitative dynamic against Yukie's will.

Despite the initial violation, Yukie develops complex, conflicted feelings toward Taketo. Her prolonged marital deprivation contributes to her gradual acceptance of his sexual attention, sparking internal turmoil between familial duty and personal desire. This involvement strains the family profoundly.

Yukie’s actions and the ensuing blackmail exert immense pressure on her daughters. Rumi adopts a protective stance toward Tomoko, striving to preserve family unity while burying her own emotional needs. Tomoko, marked by innocence, actively works to sustain family happiness despite lacking genetic ties and facing escalating turmoil. Throughout these events, Yukie remains central to the emotional upheaval engulfing every family member.