A heartfelt middle-grade novel about ex-best friends, betrayals, and revenge that is best served sour.Revenge is sweet!For as long as she can remember, Mai has spent every summer in Mystic, Connecticut visiting family friends. And hanging out with her best-friend-since-birth, Zach Koyama, was always the best part.Then two summers ago everything changed. Zach humiliated Mai, proving he wasn't a friend at all. So when Zach's family moved to Japan, Mai felt relieved. No more summers together. No more heartache.But this year, the Koyamas have returned and the family vacation is back on. And if Mai has to spend the summer around Zach, the least she can do is wipe away the memory of his betrayal... by coming up with the perfect plan for revenge!Only Zach isn't the boy he used to be, and Mai's memories of their last fateful summer aren't the whole truth of what happened between them. Now she'll have to decide if she can forgive Zach, even if she can never forget.