This is the prequel to Eroriman 2.
Our MC is lonely businessman. To entertain himself, he usually picks up a girl for a paid dates. When MC busy scrolling through the pages of the site, he found someone who's face is familiar to him. It was his niece, Mifuyu. He found hard to believe to think the quiet & sweet girl he used to know ends up working in paid date's service. She even sells her virginity. He booked her for the paid date and taking her to the hotel. MC was curious with what happened to her life, turns out that Mifuyu damaged her friend's phone and now she's trying to pay the repair's fee. MC gave money in exchange for sex, that should solve the problem. But the situation changed. Looks like Mifuyu had something else in her mind.