Twelve-year-old Song Xinyu left her childhood sweetheart Ouyang Xiu to study abroad. Four years later, Song Xinyu returned to China. Before returning to China, she had obtained a double degree. However, after she returned to China, she was forced by her father to attend a private middle school. She originally didn't want to go, but she heard her father say that Ouyang Xiu went to school there. It was okay not to go, because they had promised to be together. Song Xinyu will never forget the boy who chased her behind the car when she was about to go abroad, crying and saying: "Xinyu, you must marry me when you grow up."