Vincent is 13 years old and has a boundless admiration for his father. His father is unemployed and is mainly involved in football, pretending to become a professional trainer soon, and does not take care of his family. Vincent's mother manages everything, until one day, at the end of her tether, she attempts suicide.
Back to school for Ducobu, Léonie Gratin and Latouche. But this year, a major rival for Ducobu arrives at school: TGV, the king of cheating 3.0. While the financial situation of Saint-Potache becomes disastrous, the two dunces will have to unite their creativity to win a song contest and save their school.