Yuu, who married Kazuo Oshima, the eldest son of the Oshima family, is immediately treated coldly after the wedding. The only person she can rely on is her younger brother-in-law, Yoshio. Seeking a place to belong within the household, Yuu begins a relationship with Yoshio, but their affair is quickly exposed. Labeled an "unworthy bride for the Oshima family," she is deemed unfit and subjected to brutal training as punishment.