Shunsuke lives in his older brother's house and attends a prep school. Every day he is indulged in delusions about his beautiful and gentle sister-in-law, Nana. On the other hand, Nana is frustrated with her estranged married life with her husband. One day, Shunsuke witnesses Nana's affair. Shunsuke, who saw Nana's obscene female face instead of her usual gentle face, begged Nana. Nana's foolishness straddling her brother-in-law in the next room where her husband sleeps.
