Library

Everyone has a secret, and each secret cannot be told to others, let alone exposed... An "accident" makes four people, Zheng Qian, Mai Yihan, Xu Ziling and Bai Tong, who are in the same dormitory, become real "best friends", guarding a secret together. Three years later, a mysterious man suddenly appeared with a photo. He was an ordinary courier, but his whereabouts were always mysterious. Things happened one after another in their seemingly peaceful life, and they were caught off guard and didn't know how to face things...