When Anna and Nils meet Bob Gribble after school one night, little do they know that his true identity is Gribblebob, a goblin from the other side of the veil. As the mystery of his presence in their village unfolds, Anna and Nils's after-school routine is quite tipped on its head: they become embroiled in an adventure to save some books from a very evil witch, while also dealing with an invisible dog and two not entirely heroic heroes while making lots of new friends along the way.
