Morgan Sparks has always known that she and her boyfriend, Cam, are made for each other. But when Cam’s cousin Pip comes to stay with the family, Cam seems depressed. Finally Cam confesses to Morgan what’s going on: Cam is a fairy. The night he was born, fairies came down and switched him with a healthy human boy. Nobody expected Cam to live, and nobody expected his biological brother, heir to the fairy throne, to die. But both things happened, and now the fairies want Cam back to take his rightful place as Fairy King.
Even as Cam physically changes, becoming more miserable each day, he and Morgan pledge to fool the fairies and stay together forever. But by the time Cam has to decide once and for all what to do, Morgan’s no longer sure what’s best for everyone, or whether her and Cam’s love can weather an uncertain future.