Wendy, a changeling troll princess, returns to her rightful home, a frightening, beautiful world where she discovers her new powers, fights enemies who want to use her abilities for evil, and struggles with romantic decisions.

In the quiet seaside town of Capri, sixteen-year-old Gemma enjoys a close bond with her sister Harper and a growing attraction to next-door neighbor with Alex, but everything changes when, after partying with newcomers Penn, Lexi, and Thea, Gemma discovers she has powers that will force a terrible choice.

Gemma must battle Penn to break the siren curse and secure a future with Alex.