After scarcely surviving Alexa Delphine's wrath in the forest, Emma is left bruised, broken, and terrified for her loved ones' safety. Now she and her best friends are all on the powerful Delphines' list, and they must enter their junior year looking over their shoulders while preparing for their class's two-week cruise around Europe.

But tensions quickly stir in the high seas when Emma spots Alexa in Athens; according to Jak, Alexa is still in North Carolina with the rest of her pack.

Realizing that they're in the middle of a cold war, Emma and her friends return home questioning what the Delphines are really after-and whom. When someone in Emma's circle disappears and is found half dead, she has reason to believe that an enemy tried to warn her about it. Left with nothing but a coded riddle and her growing powers as a hybrid, Emma has one chance to expose the hunt before it pulls her loved ones under for good.