A teenager reluctantly learns to face forward rather than back in this refreshing, unusually perceptive debut. The winds of change are blowing bitterly around 15-year-old Haven as her parents break up, her father marries a younger woman, her sister Ashley turns into a termagant as her wedding approaches, and her own body becomes a stranger, topping 5' 11"" in a sustained growth spurt. To shield herself, Haven clings to the memory of a summer vacation to Virginia Beach three years ago, when her family was still together and Sumner Lee, the best of Ashley's legion of boyfriends, came along. Suddenly, Sumner is back, as charming and comforting as ever; can he rekindle that memory's magic? Displaying a flair for evocative names and well-timed plot twists, Dessen takes her tall and usually levelheaded teen through two weddings and a succession of disturbing, often comic, surprises, to a climactic explosion. Haven enjoys a nicely articulated love/hate relationship with her sister, ostensibly a superficial cheerleader type who turns out to be wiser than she seems; she helps Haven shake off her dependence on a memory (not entirely accurate, as it turns out) of idyllic happiness. Seeing everyone else building new lives, Haven starts to think about her own future, too. A worthy theme, but the chief attractions here are the appealing cast and droll humor.