Taking place in a shikumen in Shanghai from 1999 to the modern-day, Li Mo has a friendly relationship with Xiao Yu. After Xiao Yu got injured trying to go back home, Li Mo carried her on his back to her apartment. Since Xiao Yu could not go to school due to her injury, she asks Li Mo to record the lessons in cassette tapes so she may listen to the tapes and learn what she missed. Xiao Yu later responds back to Li Mo in cassette tapes and the two develop a romantic relationship with each other.
