The little girl Xu Xiaoye, who has a strong inferiority complex and autism, has been regarded as an alien by her classmates since she was a child. She meets the fat little boy Lu Zheng, who gradually warms Xu Xiaoye with a sunny heart. When her life gradually returns to peace, the genius boy Linfeng who suddenly transfers to school makes her life once again stir up waves. In the end, the warmth of the sun miraculously arrives, and she looks up quietly. It turns out that the summer sun is so warm.