It is adapted from the author's true story. That year Zhang Yangyang and He Yihui were 16 years old. They met, got to know each other, and fell in love. He Yihui said I will take care of you for the rest of my life. That year Zhang Yangyang and He Yihui were 18 years old. He Yihui left without saying goodbye. Zhang Yangyang said: I will wait for you forever!