While on vacation, Emily Windsnap finds herself swept up in an ancient prophecy as the New York Times best-selling series continues. Emily is headed to a tropical island for a relaxing vacation with friends and family. And this time, Emily promises her best friend, Shona, there will be absolutely no adventure—just plenty of fun. But somehow excitement always seems to find Emily, and before she knows it, she ends up on the other side of a powerful waterfall on a forgotten island no one else can get to. Well, no one that isn't a half-mer like Emily and her boyfriend, Aaron. The people who live on the island believe in a prophecy that foretells how they can be saved from an imminent, devastating earthquake—and this prophecy seems to revolve around Emily and Aaron, as well as a mysterious, mythic giant. Will they be able to find the giant—and fulfill the prophecy—before it's too late?