Two successful young people reunited after a long absence, recalling the green years of high school. Unable to resist the comeback of memories, they commemorated their past youth by being together. It is interspersed with campus high school memories, intentional and unintentional actions, belated crushes, and feelings that come and go in a hurry. The pounding heart is followed by heartbreaking pain. Who has never been young and been favored by youth? We are just about to forget and be forgotten. What is now is a long road, but the past is gone forever. If, if you can turn back time, you can walk back to that classroom, if the person standing on the podium is still your class teacher, will you eagerly look for another person?