Over the course of one eventful summer, nine-year-old native Mainer Delphine Crandall and Maggie Weldon, a privileged girl 'from away,' become best friends. Despite the social gulf between them, their bond is strengthened during vacations spent rambling around Ogunquit's beaches and quiet country lanes, and lasts throughout their college years in Boston. It seems nothing can separate them, yet after graduation, Delphine and Maggie slowly drift in different directions...

With her MBA, Maggie acquires a lucrative career, and eventually marries. Delphine is drawn back home, her life steeped in family and the Maine community she loves. Twenty years pass, until one summer, Maggie announces she's returning to Ogunquit to pay an extended visit. And for the first time, the friends are drawn to reflect on their choices and compromises, the girls they were and the women they've become, the promises kept and broken - and the deep, lasting ties that even time can never quite wash away...