La Frontière [The Border], which takes place during a scorching-hot summer in northern France and Belgium, tells the story of three women, Axelle, Conso and Dominique, who have nothing in common except for the fact that they are colleagues and cross the border together every day to go to work. Indeed, in order to live decently on one side of the border, in Roubaix, they prostitute themselves on the other side, in Belgium – this double life is their secret. At the end of the summer, when a thunderstorm finally arrives, giving a long-awaited break from the stifling heat, the three women unite in a gesture of solidarity much in the way one would rally the resistance. They now share a new secret that will bind them forever. What could possibly push these women, which everything opposes, to enter into such a radical lifelong pact?