yu and yuria have to live with their new father because of their mother’s remarriage. the two of them were secretly working on customs, but one day, their father-in-law called them on a 3p course without knowing it. two people who despise the manners and customs even though they have a mother. in the midst of this, yu is fired from the sex industry because of the recession. yuu, who doesn’t earn enough money, uses her father-in-law’s love of manners and begs to make full use of the erotic techniques she has cultivated. and yuria, who witnessed the two having sex, also confronts her older sister.