Late at night in early autumn, Internet writer Xiao Mo met an old woman. An unsigned letter and an old photo taken in Lushan involved Xiao Mo, Ye Zi, the landlord Song Boran's son Steven, the prodigal son Yu Feng, the eldest lady Xia Xiaoxiao, the cute idol star Xia Xiaoyu and Song and the beautiful manager Jasmine. These young people were involved in a love that lasted forty years ago. Several people also found their true love in this search.