Their unfaithful spouses have provided them with license to fool around, but there's much more at play than romantic revenge in the pairing of Ludovic (Victor Lanoux) and Marthe (Marie-Christine Barrault). After meeting at a family gathering and realizing that they're related by marriage, the attractive young duo forges a sophisticated relationship, one that increasingly looks like it might turn sexual. Perhaps predictably, some onlookers are less than enthusiastic about the evolving kinship.