The story opens with the reunion on Fire Island of three old friends: Alice and Riley, sisters in their early 20s, and Paul, 24, with whom they have grown up over two decades of summers. A laconic, outdoorsy tomboy of a young woman, Riley has always been both the idol and the opposite of her little sister Alice. With her Ivy League brain ("You're supposed to be the smart one," Riley reminds Alice deep into the story), steadfast generosity, the small cross she wears around her neck, Alice is the sort who knits scarves and hats to express love. Yet the sisters are so close that Alice feels, as they lie with arms and shoulders touching on a beach where Riley's been the star lifeguard for six summers, that the "body of her sister was not quite like a separate body. . . . Like if she thought hard enough, she could make Riley's knee bend."
The sisters are as deeply connected with their summer neighbor Paul, only son of a largely absent mother and a father who died of a drug overdose when Paul was 4. He and Riley -- same age, same size until recently, same physical agility -- have always been best friends. Riley is Paul's "equal, his rival, his flipside. . . . In some ways, he found it hard to distinguish himself from her." Alice isn't his friend. She is "something else, neither more nor less but not the same." The difference is love, as inevitable for Alice and Paul as tomorrow's sunrise over the ocean. But what of the three-point balance of "what he'd had here on this island with Riley and Alice . . . the best and most lasting thing in his life"?
