Mu Zixing met a beautiful boy, Sinan, when she was five years old. He became her childhood friend. During their first meeting, Zixing was rejected by Sinan while she played with mud. Zixing grew to believe that she was hated, but did not know that Sinan, who was enraptured by her infectious cheerfulness and smile, had slowly fallen in love with her. And this love only grew deeper and deeper with time.