Ethan and Lena think they have faced the challenge that came with her claiming, but really it's only been postponed . . . and cost them something. Lena's changed and Ethan can't figure out why or what to do about it. Even as she seems to be pulling away, Ethan's trying to reach her. 
 Ethan finds out his role in all of this and uncovers what really happened at Lena's sixteenth moon, but that doesn't keep him from having to face the seventeenth moon. Luckily, he has quite a few people in his corner. 
 A lot of people facing themselves, becoming what they were really meant to be and not all that comfortable with it. Very much a young adult book in that respect.