The story of Antoine Doinel – aged twelve and a half – begins on the day he is given a severe punishment at school to do at home that evening. It happens that he is unable to do it. So, the next day, not daring to go back to school, Antoine, together with his best friend, René, discovers the joys of playing truant. That afternoon, he comes across his mother on the arm of a stranger. He is overwhelmed by the sight of this and he runs away. He ends up in a police station, then in a Delinquents Observation Center. Will Antoine one day come to terms with life?