When Maggie and Emily meet as girls on the Nantucket beach, they are instant best friends--even though Emily's mother would much prefer she play with the daughters of senators and statesmen than a seamstress's kid like Maggie. But after many golden summers spent building sandcastles and sharing their dreams for the future, Emily and Maggie grow apart. In her twenties, beautiful and spirited Emily worries she'll never amount to more than the glittering wife of a successful husband, while hardworking redheaded Maggie scrimps and saves her pennies, wondering if she'll ever have the luxury of a passionate romance. It seems they have little in common...until Cameron Chadwick appears on the island. A wealthy Wall Street broker, Cameron takes moonlit walks on the dunes with Maggie and romances Emily in Manhattan with lavish nights on the town. When both women discover they're pregnant, it looks like the end of their already-distant friendship. But as Maggie and Emily struggle to decide what their lives will be, they realize more than ever before how very much they need a friend.