Claire and Bruno have been together in a settled relationship for twelve years. They're an institution. While spending a day with friends in their family home, bored with playing the role of the perfect couple, they pretend to split up. To their great surprise, they realize that no one around them actually thought their relationship was in good shape. Family and friends take it upon themselves to find reasons for the break-up. Claire becomes aware of how dissatisfied she feels, while Bruno realizes he must pay more attention to what's ahead. But is it too late?