My cousin, who I met after a long time, was completely grown up ... Five years ago, Nanami, who goes to school, has a relationship with her cousin Teppei from a little momentum. However, I didn't have sex, I just taught Teppei, who doesn't know a woman, how to masturbate. Both of us were doing something wrong at that time. Since then, it has become awkward and Nanami has been far away from him. Then, as the days passed, the two would meet again ...