Pierrot is a 13-year-old boy, discreet and locked up, who has lived alone with his father since his mother's death, which occurred ten years earlier. Although disturbed by this tragedy, the boy does not keep any conscious memory of the deceased. One day, Pierrot is witness to an ordinary humiliation inflicted on his father on the public road. He remains deeply marked by this dramatic episode, which resonates painfully in him and soon produces chain reactions. This event, however sadly banal, reveals the great frailty of Pierrot, which is dangerously shifting into madness.