The 4th series of "Documentary Incest Incest" series that approaches forbidden relationships that should never be violated! This time, the sister-in-law who fell in love with her virgin brother-in-law is an idol otaku, and she tries various tricks to take her virginity, but her brother-in-law doesn't even look at her. Her out of control sister forces her to make an appointment with her brother-in-law. Her promise is, "If you don't graduate from virginity by her next birthday, your sister will take it away." There is no way a brother-in-law who has no dating experience can graduate from virginity. What will be the fate of these siblings?
