男主家人遇难，独自一人只能寄宿在叔叔家里，叔叔的女儿对男主照顾有加，男主也很尊敬这个姐姐，而男主在跟女友发生关系后，才发现自己根本不懂性技巧，无奈之下只能求助姐姐，而姐姐为了帮助男主有更好的性体验，就跟男主做爱来传授经验，而两人的亲密接触之后，男主发现自己爱上了姐姐，提出跟女友分手，不久之后，男主得到了一个更加劲爆的消息，他的前女友竟然跟叔叔在一起了！

Yasuo is staying at home with his father, Tassuke, who is just like his uncle. However, Tase’s daughter, Seiko, has an outspoken affinity for Yasuo from the first day. Seiko’s aggressive body attack that did not win the lust Yasuo told her that she was like her cousin’s sister I can not refuse and start to spend a hot night.