Nonoka and Hinano are two high school sisters living happily in the countryside with their stepfather, Yoshio. However, one day, their stepfather passes away, and their stepbrother, Koji, returns from the city and takes them under his care. At first, Koji behaves kindly, but gradually his gaze towards the sisters turns to one filled with lust, and he begins to exert a sinister control over them. Nonoka endures desperately to protect her younger sister, and Hinano, despite being crushed by fear, clings to her older sister. However, Koji's abuse escalates, and eventually he brings a wealthy man into the house and forces the sisters to sell their bodies. With no escape in the dark house, the two support each other and try to survive with a glimmer of hope in their hearts. As the sisters hold hands in front of the Buddhist altar, the shadow of Koji looms everlastingly behind them.