On 1 January 1993, two customs officers, one Belgian and the other French, learn of the future closure of their small customs post situated between Courquain in France and Koorkin in Belgium.

Both a hereditary francophobe and an over-zealous Belgian customs officer, Ruben Vandevoorde is forced to join the first Franco-Belgian mobile squad. The first French volunteer for the squad is Mathias Ducatel, Vandervoorde's personal bete noire. Ducatel also has the misfortune to have fallen in love with Vandervoorde's sister Louise, who is afraid to show her feelings towards him because of the trouble she knows it will cause within her family.