The Dragon's Codex: Dragonfall, Book 2 (Unabridged‪)‬

After narrowly escaping Rogue City, Ben travels north into the Deschutes Territory in hopes of finding sanctuary, if only for a little while. His respite is brief and his hunters are persistent. Within a few days he's on the run again.

Ben must negotiate the desert, the underground, and the unknowable perils of magic if he is to recover the Dragon's Codex, the only known book of magic in the world, and his best hope for finding a way to stand against the wyrm.