Risa broke up with her boyfriend half a year ago and now has a physical relationship with a man.She's a sex friend, she says, but her partner is a much older man.We met in high school.The man was a biology teacher.Risa doesn't have any unusual hobbies, she's just a normal girl who likes to chat.She was a freshman in high school at the time and suddenly fell in love with the biology teacher.He wasn't good-looking, but he looked younger than his mid-40s and seemed a bit eccentric.He always teaches with a reluctant look.He didn't make eye contact with the students, and didn't seem to have any interest in having a conversation with them.At first, she and Risa only saw him as a dull old teacher.However, he, who was usually mumbling, suddenly started talking about science fiction in class.If a human clone was created, he kept it as a spare for himself, but one day the cloned human beings would rebel. It was sparkling and had a glowing heat.He may have found Risa's eyes alone.What is this person, interesting... out of curiosity, Risa visits the science department where he is an advisor.This science club was not popular, and although there were several members, they were all ghost club members, and the biology teacher was just playing around in the club room.Taking advantage of such a situation, Risa went to the science club room after school almost every day.Risa really enjoyed talking with her teacher.They were nearly 20 years apart in age, and above all, she was a teacher and a student, so there was no way they could confess to each other. .How many times did she dream that Risa interacted with him in her club room?In the end, it didn't come true, and the shaky relationship continued until her graduation.After that, Risa went on to school, and she got a boyfriend close to her age.She wonders why she wasn't able to confess to her at the graduation ceremony, and she has a vague feeling.She then broke up with her boyfriend of nearly three years, and suddenly decided to go to high school.It wasn't that she had no ulterior motives.If only that biology teacher was still in the science club room.As expected, he was still grading quizzes alone in the club room.Risa couldn't help but hug him.She didn't care if the test sheets she was marking were scattered on the floor.