OVA
Description
Rumi Kitazawa is the older daughter of Yukie Kitazawa and has a younger sister, Tomoko. Her family faces significant instability driven by external pressures and internal conflicts. This turmoil begins after her mother becomes entangled with Taketo Nogawa and his father following a car accident, leading to both Rumi and Tomoko facing exploitation through blackmail. Rumi assumes a protective role toward Tomoko, believing she must shield her younger sister from the family's distress, suppressing her own emotions and needs to maintain family unity.

The return of her father intensifies the family's challenges. He develops inappropriate urges toward the now-grown Tomoko and struggles to resist them, while Taketo remains involved in the family dynamics. Rumi continues striving to hold the family together despite mounting tensions. During this period, Rumi engages in a sexual relationship with Taketo, who lives with the family, alongside her mother's involvement with Taketo and her father's fixation on Tomoko. Rumi navigates this complex environment while trying to preserve family normalcy.

Rumi's relationship with Tomoko remains central. She feels a strong duty to protect her innocent sister, who desires family harmony. Despite Rumi's efforts, Tomoko becomes involved in the escalating sexual tensions within the household. At one point, Rumi and Tomoko engage in sexual activity together, reflecting the extreme dynamics and eroding boundaries within the family.

As the family deteriorates further, Rumi faces new challenges when her father acts on his urges toward Tomoko. This triggers a breakdown in the family structure, culminating in a proposal for all members to engage sexually with one another to manage the situation. Rumi's role shifts as she navigates these developments, continuing to suppress her emotional needs while adapting to the increasingly chaotic environment. Her background involves maintaining a facade of normalcy amid exploitation and disintegration, with her protective instincts toward Tomoko defining her throughout.