Everyone probably has a person in their heart that they never forget. A name mentioned by chance caused thousands of waves in the heart of the female photographer Geng Geng (played by He Landou), touching the switch of memories, and the exciting teenager Yu Huai (played by Chen Feiyu) broke into her thoughts again. That was the best time in memory. The poor student Geng Geng and the top student Yu Huai became deskmates, and also met Jian Dan (played by Wang Chuyi), Beta (played by Zhou Chuchu), and Xu Yanliang (played by Chen Shuai). The campus is full of ignorance, immaturity, heartbeats and bravery exclusive to boys and girls, and Geng Geng and Yu Huai also have their promise. After the college entrance examination, when Geng Geng was looking forward to the fulfillment of the promise, Yu Huai suddenly disappeared. Seven years later, the two met again. Can Geng Geng get the answer to the words that Yu Huai did not say that year and the secret of his leaving without saying goodbye? This lingering past made the two face emotional choices again. This film is adapted from the novel of the same name by August Changan.