The Dark Hills Divide by Patrick Carman

This series is like nothing out there. The world created by the author is like an island in the sky. Most of the population who live there, don't know about the other parts of the land. 


Warvold has traveled the world and learned of its good and bad qualities. He built rounded walls around the 4 main cities and connected them with walled streets. He is trying to protect the citizens of these town from what they do not know. 


The main character, Alexa, is charged with saving the world she knows and the parts she doesn't even know exist. Warvold has secretly entrusted her with the mission as his final wishes. He pre-planned everything without anyone knowing except for Alexa and the dwarf and animals that he wants to help her. Alexa's journey is one that only a 12-year-old child can make. She begins to learn about the world she lives in and the secrets it holds.