Yusaku, who is owed to his graduation thesis, is at the mercy of his bewitching and free-spirited sister-in-law, Maki. Knowing that she is being peeped, she boldly masturbates, drinks wine while showing her open crotch at the dining table, and when her brother goes on a business trip, she indulges in a rich slut play, saying that it is your role. One night, when her brother is drunk and falls asleep, Maki approaches Yusaku like a female cat in heat, telling him to wait until morning.