All Yuan Zhinan left behind when she passed away were a letter and an invitation to a school reunion. Attending the reunion in lieu of her late elder sister, Yuan Zhi Hua accidentally runs into Yin Chuan, on whom she had a crush when she was younger. As old memories are evoked, and correspondences travel through different contexts and times, Zhi Hua slowly uncovers the intricate story of the trio. (Source: WeliWelo at MyDramaList)