This is the story of two sisters who lost their parents and lived hard lives... The year is 1985. As the world boomed with the bubble economy, the sisters were forced into poverty. In a situation where it was difficult to even live a normal life, the older sister, who was a small but valuable source of income, suffered a serious injury to her leg. Living expenses and expensive medical bills... the younger sister turned to prostitution to survive. The older sister could hear the younger sister's moans through the sliding door... She felt a strange excitement along with a sense of guilt. Her hand reached for her crotch...