Although Yuzuki's older brother has a wife, that is not enough. He is always looking for ways to have incest with his own sister. He has a lustful personality and likes to pervert. Because he lives in the same house, he can always monitor every move of his little sister. From peeking at her bathing, playing with her underwear... and other depraved expressions, he did them all discreetly. Until one time his younger sister discovered him playing with her pretty panties, he was very embarrassed but then also surprised because he saw that she seemed to like this. The two of them started to develop feelings from here, the girl's secret sexual and erotic times also happened from there. Gradually, because they knew how to take advantage of opportunities, they were finally able to secretly have sex many times. with each other while family members were unaware of what was going on.
