Miranda and Adam, high-school sweethearts now in their late fifties, arrive by chance at the same time in Rome, a city where they once spent a summer deeply in love, living together blissfully. At an awkward reunion, the two—who parted in an atmosphere of passionate betrayal in the 1960s and haven’t seen each other since—are surprised to discover that they may have something to talk about. Both have their own guilt, their sense of who betrayed...