Fabled Resurgence (Fabled Series #2).

BOOK TWO IN THE FABLED SERIES:
“We must protect our borders from the humans. They will inevitably come and try and take our land. Now that their own cities are uninhabitable,” Riona was arguing. “We cannot allow that to happen.”
The earth has swept aside the human world. Hannah, Elliott, Luke and Ruth, bereft of their beloved teacher, face an uncertain future at the hands of the re-emerging fabled races who now hold the fate of humankind in their hands. In the midst of this new world full of wonders and dangers, in equal measure, the children struggle with fateful decisions of their own.