Toute la brigade de gendarmerie de Charnay-Lès-Mâcon (71) se prépare à l’annuelle Grande Fête des Jardins. Mais l’arrivée d’un jeune stagiaire désinvolte débarqué tout droit de la capitale et de deux voleurs de nains de jardin va venir bouleverser leur organisation bien huilée…

Claude and Marie Verneuil will soon be celebrating their 40th wedding anniversary. For the occasion, their four daughters — Isabelle, Odile, Ségolène and Laure — decide to organize a big surprise party in their family home in Chinon. They also decide to invite, each, the parents of their respective husbands — Rachid Benassem, David Benichou, Chao Ling and Charles Koffi.

Looking for a baby-sitter for the night, Marc Schaudel entrusts his son Remy to the care of his employee Franck, a straight man. But the thing that Marc doesn't know, is that Franck is getting 30 years old this weekend and that his son Remy is a very capricious child. The next day, Marc and his wife Claire are awakened by a call from the police. Remy and Franck are missing, and the house is totally devastated. The police finds a camera in the leftovers. Marc, Claire and the police start watching the video that has been recorded the day before during the night and find out what happened to Franck and Remy.