Li and his wife A Yu run a small business in Thailand and enjoy a happy home life with their two daughters. When their eldest daughter is violently assaulted, blackmailed and left traumatised by another student, her parents intervene, leading to a dead body which needs to be hidden, and every trace of the boy buried to cover up the accident.
All Yuan Zhinan has left behind when she passed away is a letter and an invitation to a school reunion. Attending the reunion in lieu of her late elder sister, Zhihua accidentally runs into Yin Chuan, on whom she had a crush in her youth. As old memories are evoked, and correspondences travel through different contexts and times, Zhihua slowly uncovers the intricate story of the trio.