The film starts in the 13th arrondissement of Paris in 1984. Robert Pinot is a police officer as ordinary as clumsy. One day, he stops a certain Josyane, a young drug addict who is also doubled as a pickpocket, nicknamed Marylou. Having discovered that she comes from the same village, Nanteuil, then him, he takes compassion for the young girl and decides to take her under his wing to keep her away from Tony, a dangerous dealer with whom she is in love.

The unusual day of a young pharmacist's assistant, between Deauville and Cassis.

The Robinards form a family divided into two irreconcilable clans: the Léonce branch and the Sébastien branch. That day, the village of Boissy-sous-Saint-Yon was abuzz with activity: at the cemetery, the grandfather, Sébastien Robinard, was buried. At the same time, Marcel Robinard, a descendant of Léonce, was getting married in church. Not to mention a bicycle race and a parade. All these events collide.