Class 28 of Wutong Middle School is a well-known problem class. Underachievers, art students, sports students, and bad boys gather here. The boys' gang headed by Song Chen (played by Ke Yanxi) and the girls' gang headed by Qin Miaomiao (played by Xiong Jingwen) are dissatisfied with each other, and the class is in chaos. One day, Class 28 received a letter, which claimed to be sent by them collectively one year later. The letter said that the head teacher Tan Ruiming (played by Qin Hai) who was about to be transferred would change Class 18 and become the most important person to them. However, one year later in the future, Teacher Tan left them forever. In order to achieve a youth without regrets and reverse history, the teenagers decided to challenge impossible tasks one by one according to what the letter said...