At first glance, Leyla and Tristan seem like the perfect young couple. They're traveling together to a remote island, to where Leyla's childhood friend Stella has invited them. However, it soon becomes clear that something mysterious is going on. Numerous couples have arrived during the final days of summer to see the world through the eyes of someone else. Leyla and Tristan meet Fabienne and Mo over a festive dinner. They perform the ritual of exchange and experience the change in their perceptions. Leyla, in particular, has never been happier, but when she refuses to return to her old self, the situation threatens to spiral out of control