After an incident at school, Tu Wei befriends the introverted Yan Shuo. One day, Wei takes his new friend home to play video games. Once at Wei’s house, Shuo cannot believe his eyes: the house is clean, bright and beautifully decorated – Wei lacks nothing. Shuo is invited to join them for dinner, and at the table he tells them that things are a lot worse at his house; his mother is long dead, his father drinks too much and abuses him sometimes.

Wei’s mother feels pity, while his father sees in Shuo everything his own son lacks: interest, intelligence and discipline. Gradually, Shuo becomes the fourth member of the family, something Wei does not like at all. Is this bound to go wrong?