This article is for you who had a serious love in your youth. Many years later, we are both happy, but occasionally we have some regrets. You are not the one who gives me happiness. Lu Yining, a smart girl with a slight disability, has been secretly writing letters to Qin Sang. This is the biggest secret in her youth. Xu Yinyin, who has been playing the piano since childhood, is the goddess of boys, but she has never been able to wait for the confession of her childhood sweetheart Yi Qianshu. The naive and daring flower bud gave the dull and silent academic tyrant Xu Changyang the courage to resist his mother for the first time. On the other side of the world, Yi Qianshu is troubled by the affair of his wealthy businessman father; under Qin Sang's appearance of infinite glory, there is a life full of holes caused by his terminally ill father... Those once brightest heartbeats that will never come back will remain in everyone's heart forever. Just like the begonia flowers blooming at four o'clock in the morning, it is an eternal poem. To have it is to be lucky. It cannot be chased or kept.