``If I have one more chance, I'll live my life without making any mistakes this time...'' - That's what the old man (45) wished for, and for some reason he becomes a high school girl. Rentaro, a middle-aged man who was popular in high school and is proud of that, spends his days being ridiculed by younger employees at work. But one day, you suddenly get a time leap and have to start over your high school days...!? You can live a popular life again! For a moment, Rentaro thought that he was not in his "past self," but in the body of a "plain high school girl in his class." Rentaro is confused. And we learn the true nature of the class at that time. Was my “popular period” an illusion?