Rock Jaw: Master of the Eastern Border is a graphic novel, the fifth book of a 9-book series called Bone. At the end of the fourth book, Phoney Bone's plan to capture the dragon unintentionally succeeds, but the rat creatures come and show the townsmen who really is the enemy. The dragon and some mysterious warriors ward off the rat creatures. Then the war officially begins with the humans aware. In this book, Smiley and Fone Bone head into the mountains to set their baby rat creature loose. However, they encounter a big mountain lion named Roque Ja. He doesn't like intruders on his mountain, and tries to kill them. Luckily, they, along with the baby possums who followed them, meet some new friends who help them find hiding places. They find an escape, but then encounter another enemy. Roque Ja and the new enemy fight, with all the little creatures stuck in between. Will the Bones and the little creatures escape, or will they be stuck in the mountains forever?
I love this book because of how detailed and interesting the storyline is, with how they discover even more mysterious ancient secrets in the middle of the book. This was personally my favorite book of the Bone series because of all the new characters and their unique personalities.