A love story revolving around childhood sweethearts, Ling Chao and Xiao Tu, who journey through youth and share experiences in sadness and joy together.

Since he was a child, Ling Chao always knew that his mother preferred daughters. Coincidentally, their neighbor's family has a daughter, Xiao Tu, who is the same age as him. Ling Chao eventually became her god-brother. The both of them have grown up competing with each other, so he demands perfection in everything. He is the smartest child in kindergarten with a high IQ, but his outstanding performances are not as good as Xiao Tu in the eyes of his mother. Due to the lack of love from his father, Ling Chao developed a sensitive, independent, and precocious personality. His only friend is Xiao Tu, and only Xiao Tu is in his heart. When he grows up, he understands that he can't do anything without Xiao Tu, because he has unexpectedly fallen in love with her, but he has never admitted it.