Tenjin is a 27-year-old teacher who conducts additional courses for students taking the middle and high school entrance exams. Although he is talented in teaching junior high school students, Tenjin does not like children. Being battered by his brutal life, he is cold-bloodedly satisfied with doing his job while raising a fellow university student. But one day, when Tenjin was teaching in the fifth grade, one of his students hugged him tightly and told him she loved him. This was noticed by a 14-year-old high school student named Seika. She blackmails Tenjin by forcing him to give her “private lessons” at night.