All marriages are a mystery to outsiders, they say, and François Ozon's new film succeeds in shining a light on one such mystery while somehow keeping its essential core of unknowability intact. 5x2 shows five scenes from a modern marriage in reverse order, like Pinter's Betrayal. We see its disintegration from the final calamity to its genesis, and gain a stunning insight into an ordinary middle-class relationship: that of Marion (Valeria Bruni Tedeschi) and Gilles (Stéphane Freiss). First, the divorce proceedings, then an unhappy dinner party, the birth of the couple's only son, the wedding and finally the first meeting. The result is a shrewd, compassionate and often quite brilliant essay in the secret theatre of relationships.