After three years of flowers blooming and falling, the clouds are rolling and relaxing, the scenery remains the same, but the childhood sweethearts Yang Muxi and Mu Jianping are far apart. Yang Muxi met Yunxi by chance on her way to the university by train. The two had not known each other before and became close friends. However, their fate did not end until they went to university, and they discovered that they were roommates. The mischievous Yun Xi and the athlete Leng Feng are happy enemies that make people laugh. On the other hand, Yang Muxi never forgot Mu Jianping, but found that he had always treated her like a sister and had a girlfriend whom he loved deeply. After being grieved, she discovered that Shui Ruohan had a crush on her, but Mu Xi only knew how to escape...