Time is a love letter, to whom it may concern. There is no "what if" in life. But what if you are younger by 10 years, what would you want to change? One day, Shi Zhao Yu and Kai Jia received an invitation from their university buddy Ruo Bi to come back to their university days' secret base "Clocktower". This "Clocktower" is, in fact, an abandoned school classroom/lab-the secret base where Zhao Yu, Kai Jia, Ruo Bi, Jun Ren, Hai Meng and Zhi Ni used to get together. On that day, by the time everyone arrived, Ruo Bi was standing on the rooftop outside the clock tower. When everyone was nervously shouting out to Ruo Bi, a light suddenly flashed from the clock on the wall...By the time Zhao Yu opens his eyes again, he is back to the year 2007 when he was in year 2 of University that year. After several failed attempts of trying to get back to the year 2017, Zhao Yu decided to re-enjoy youth, rechallenge the basketball match which he had once lost and also try to pursue the dream girl Ruo Bi whom he once missed the chance. But towards Kai Jia, he can't help it and still cares about her; especially so when Kai Jia and Jun Ren are getting closer and closer... Can Zhao Yu use this chance to learn how to face himself honestly and learn how to love? Cherish the precious things in youth?