This story happens in the southern part of Beijing. Lee, the motor-taxi driver's and his family live in a dilapidated tenement yard. His disobliging sister always asks him for the relocation of the tenement yard and urges her brother's family to repay the money. Kai's classmate, named Er Dong, a bad boy whose father is the lecherous principal, frames a case against Kai that he had stolen the monitor's cell phone. The teacher always looks upon on Kai, he denounces Kai without any investigation and gives a slap on Kai's face. Kai hit the teacher with a brick in great impulsion and the principal dismissed Kai. Because of this, Lee has to beg the principal for retraining the punishment on Kai, besides, Lee has to offer a bribe for his son. At last, grandpa passed away quietly, lee was arrested by the police because of the prostitute's tip-offs. Kai stands lonely on the rooftop of his dilapidated house, sees the blinding sunlight and hears the cockcrow......