On the eve of her 18th birthday, a blithely happy princess named Aisling is confronted by a hardscabble teenage rogue named Forgive-Me-Not. Aisling quickly learns a few hard truths: she’s not the biological daughter of the king and queen. She’s not the heir to the throne. She’s not even human. Aisling was a changeling, switched at birth as part of a fey scheme and power play. Forgive-Me-Not, the true heir, was raised in the faerie world where she was toyed with and mistreated for much of her life. This kicks off a long and arduous journey in which the two realize both how different their lives are, and how their different lives put them into a place where they can help each other and see each other in ways no one else can.