Lin Miao's Teng Jing has been a good friend since childhood, one is cheerful and lively, the other is gentle and kind. In high school, Lin Miao and the cold and lonely Jiang Ran were in the same class and became good friends. The understanding of friendship between the three girls is at the same time jealous of each other. Lin Miao and Teng Jing fell in love with Su Yan, the monitor of the class next door who had excellent grades, and Luo Zicheng, a kid from a wealthy family, pursued Jiang Ran... The ignorance in their youth was as sincere as the blue they loved, pure and melancholy. Lin Miao's tears, Teng Jing's provocation, Su Lian's helplessness, Jiang Ran's tenacity, and Luo Zicheng's persistence. After many years, they will look back when they have matured. Those blue colors seemed to be immersed in water, blurred into one piece. Although they could not be seen clearly, they were enough to make people burst into tears...