The 30-year-old Liao Tian (Tong Wei) suffered a midlife crisis, failed marriage, and no career, and he was reduced to cleaning toilets in KTV. By chance, he met his old classmate Liang Dong (Wang Liang), who had become a "big brother" figure, and was forced to attend a high school reunion. Here, Liao Tian met his old friends and the school beauty he liked back then, Xue Man (Huang Rong), which evoked his memories hidden in his heart and the most beautiful and regretful youth time. The changes in everyone also made Liao Tian feel the sadness of the passing of youth and the inability to return. Liao Tian used his own way to express his love for youth.