The serious young girl Haru-chan couldn't keep up with her classmates' lewd conversations and was secretly troubled. One day, she mustered the courage to visit her homeroom teacher's house on a day off to learn about sex. However, that teacher was a pure pervert who went to brothels every Sunday. Initially, he tried to quickly shoo Haru away because he had an appointment at a brothel, but since she was so persistent, he took advantage of her curiosity and began to manipulate her developing body. Haru, taking the teacher's words at face value, gradually allowed her young body to be trained according to his wishes...
