His daughter Risa, who is about to get married soon, and her boyfriend, Akio. Risa's mother, Yu, smiled at them. However, one day, after getting out of the bath, Yuu witnesses Akio holding his own underwear. Since then, she has felt that Akio's behavior is strange. On another day, when she was alone with Akio, Akio asked for his body, saying, "Just once."
