a serious and innocent girl, riena, was troubled because she couldn't keep up with her classmates' conversations about sex and had no one to consult. one day, she mustered the courage to visit her homeroom teacher's house on a day off to learn about sex. but that teacher was a pure lecher who went to a sex shop every sunday, and he tried to get rid of the student who had come to his house because he had a reservation at the sex shop. however, she persisted, so he took advantage of her curiosity and played with her developing body, and riena, taking the teacher's words seriously, gradually became trained by him.
