Sisters Mari and Megumi have lived by relying on each other since their mother left home and their father died. A woman who calls herself her younger sister, Rui, appears before the two of them. In contrast to Megumi who is happy that she has more sisters, Mari is distrustful of this woman who suddenly appeared. One night when they began to live together, Rui gently comforted Megumi's aching body and tasted the deep pleasure of women. And a few days later, Rui gets naked in front of Mari and urges her not to avoid herself. Mari was convinced of something while listening to her story.
