Zhixing, a real estate agent who muddles through life and lives under the haze, has been cared for by his mother since he was a child and has been living an ordinary life. One day, Zhixing met his elementary school teacher, PE teacher Huang Sir. In order to fulfill his deceased wife's 10-kilometer run agreement, Huang Sir practiced and participated in the competition even though he was sick. At the same time, Huang Sir's student, Tianxin, a fat girl, lost weight and risked her life to complete her first 5-kilometer street run in her life in order to run with her idol. Zhixing saw that Huang Sir and Tianxin were working hard for their goals, but he was lost at the crossroads of life. His life without air continued to deflate every second. Until one day, a memory from 20 years ago suddenly came to Zhixing, illuminating the haze in his heart. This time, Zhixing vowed to cheer up his life!