Young Mollie traverses eerie, perilous lands to retrieve her baby brother, Thomas, from the Kinde Folke, malicious sprites who snatched him and left a hideous changeling in his place.

Changeling Bartholomew Kettle, having been locked away by his mother to protect him from humans and faeries who would want him dead for being half-human and half-faery, witnesses another changeling being kidnapped by a beautiful and mysterious figure, and, after hearing of the bodies of changelings being found dead and marked with a red tattoo, he realizes he is the next target and must figure out a way to stay alive.

Nine months after her adventures in Faerie, Izzy is reunited with her old friends to help find the lost King's Key before an evil witch can use it to steal Changelings who live on Earth.

Morgan Sparks and her boyfriend Cam have been best friends since they were children, but just before their shared sixteenth birthday Cam confesses that he is a fairy who was switched at birth with a human child, and now the fairies want to switch them back.

Toklo, Kallik, Lusa, and Ujarak finally arrive at the legendary Last Great Wilderness, thinking it is the end of their long journey, but they discover that their true mission has really just begun.

At age twelve, grave robber Thomas Marsden discovers a boy who looks just like him in an unmarked grave and begins a journey of discovery as he learns of faeries trapped in London and their hope that he can return them to their realm.