The book, Stormchaser, is the sequel to Beyond the Deepwoods. The story continues with Twig and his father, Cloud Wolf, sailing into Undertown, the only real city in the Edge. It lies in the shadow of Sanctaphrax, the academic town on top of a giant floating rock. To keep Sanctaphrax from floating away, it needs stormphrax, a heavy substance created by lightning. An evil scholar once made a substance that can turn any water clean from crushing stormphrax, but no one has ever been able to make more. People keep trying to make it with stolen stormphrax, therefore threatening Sanctaphrax with floating away! Twig and his father are sent secretly to find more stormphrax to keep Sanctaphrax from floating away. To find out what happens to Twig and the rest of his fathers crew, read the book.