After a senior year filled with ups and downs and a notebook that almost cost her everything she cared about most, life has finally fallen into place for Emily Abbott. With graduation behind her and college acceptance a certainty, Emily is looking forward to a perfectly predictable summer. Her plans for a cushy job on Cape Cod with best friends Josie and Lucy, and time to finally enjoy a normal relationship with Luke, are just what she needs. But when her mom springs a surprise on her and an accident upends Luke’s plans, the summer ahead brings changes that Emily couldn’t have possibly prepared for or predicted. As the warm weather wanes and college looms in the future, Emily is faced with choices that no handbook can help her navigate. And she’s about to learn that the consequences of her decisions will not only tear apart the relationships she’s worked so hard to get right, they’ll also test whether true love is about holding on or knowing when to say goodbye.

Emily Abbott has always been considered the Girl Most Likely to Be Nice -- but lately being nice hasn't done her any good. Her parents have decided to move the family from Chicago back to their hometown of Boston in the middle of Emily's senior year. Only Emily's first real boyfriend, Sean, is in Chicago, and so is her shot at class valedictorian and early admission to the Ivy League. What's a nice girl to do? Then Sean dumps Emily on moving day and her father announces he's staying behind in Chicago "to tie up loose ends," and Emily decides that what a nice girl needs to do is to stop being nice. She reconnects with her best friends in Boston, Josie and Lucy, only to discover that they too have been on the receiving end of some glaring Guy Don'ts. So when the girls have to come up with something to put in the senior class time capsule, they know exactly what to do. They'll create a not-so-nice reference guide for future generations of guys -- an instruction book that teaches them the right way to treat girls. But when her friends draft Emily to test out their tips on Luke Preston -- the hottest, most popular guy in school, who just broke up with Josie by email -- Emily soon finds that Luke is the trickiest of test subjects . . . and that even a nice girl like Emily has a few things to learn about love.

There are two kinds of people on the island -- those who leave at summer's end...and those who are left behind. Kendra and Mona are best friends, local girls who spend their summers catering to rich tourists and the rest of the year chafing against small-town life. Then Mona's mom marries one of the island's rich summer visitors, and Mona joins the world of the Boston elite, leaving Kendra and Martha's Vineyard behind. When Mona returns the following summer, everything is different. Now Mona spends her days sunbathing with her private-school friends, while Kendra works at The Willow Inn -- a job she and Mona once hoped to do together. Unlike his sister, Mona's twin brother Henry hasn't changed. He's spending his summer the way he always has: with long, quiet hours fishing. Early mornings before work become special for Kendra as she starts sharing them with Henry, hoping he can help her figure Mona out. Then Kendra hatches a plan to prove she's Mona's one true friend. She'll uncover the identity of the twins' birth father, a question that has always obsessed Mona. And so she sets out to unravel the seventeen-year-old mystery of the summer boy who charmed Mona's mother. But are some secrets better off staying buried?