Rivers of Fire (Atherton #2)

The world of Atherton has collapsed and the three levels have become one. Humans and monsters, once separated by vast cliffs, now roam the surface of Atherton together. The inside of Atherton--where the most troubling secrets are hidden--has been breached. While Edgar embarks on a life-or-death quest to find Atherton's mad maker, his two friends, Samuel and Isabel, venture through dangerous underground realms, confronting deadly cave dwellers, rivers of fire, and waters of life.

Atherton is not what it seems at all, but something far more dangerous, with a history locked inside the mind of a madman and a future beyond Edgar's wildest imagining.