Marina-chan, a young girl, couldn't keep up with the naughty topics of her classmates at all, and was worried about her secretly. One day, she visited her teacher's home on a holiday to have her homeroom teacher teach her about sex. However, the homeroom teacher is a purely erotic teacher who goes to customs every week, and at first he was paying off Marina-chan who visited the teacher's home to go to the customs he had reserved, but she was so persistent that she was curious. Taking advantage of it, playing with the body in the growth process, Marina-chan also takes what the teacher says seriously and gradually becomes dominated.
