After thirteen years in Germany, Fernand is coming back to his wife and his restaurant. But since his disparition, his wife as made her life with a norman chef, sympathetic but a specialist of butter's cooking when Fernand cook only with oil!
Mr. Pelletan's rascal son Bébert son got another F for playing in class. His punishment is an essay on the Merovingian king Dagobert. All they know is he had eight wives and reunited Francia. The ignorant knave's irreverent imagination turns that into a harem and a ludicrous war without armies, loaded with anachronisms, in a race against rival king Charibert for the crown of Reims. The king's right hand, archbishop Eloi, the later patrons saint of carpentry, is portrayed as an inventor.
Aimé Morin, a good-natured bookseller, is also one of the candidates in the local elections of his small town. He is well-liked by most but he also has political enemies. Among them is Lagarde, a journalist close to the latter. Lagarde takes advantage of Morin being on holiday in Paris to try and tarnish his reputation. His machination unfortunately works and poor Aimé finds himself mistaken for a sex maniac.