Dinotopia: The World Beneath (Dinotopia (HarperCollins))

After they are shipwrecked on a mysterious island called Dinotopia, Professor Arthur Denison and his son, Will, discover an awe-inspiring new world where dinosaurs and humans have lived together peacefully for centuries. They have only begun to adjust to this remarkable civilization before heading off on separate quests. Will takes to the sky as the pilot of a giant pterosaur known as a skybax, while Arthur leads an excavation deep underground to discover the origins of the world beneath Dinotopia. Little does either of them know of the dangers they are about to face ...