Julia used to be the perfect big sister: she played great games and took good care of Cassie. Now life at home revolves around Julia and her daughter, Addie. No one pays much attention to Cassie: not to her competitive swim meets, and not to what's gone wrong with her friends.

When Julia confides in Cassie that she'll be leaving with Addie--without telling their parents--Cassie jumps in the car, too. As the days of lumberjack breakfasts and hotel pools start to add up, Cassie has to wonder: Could the sister who seems to be the source of all her problems also be the friend she's missed the most?