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
