Irish movie of a boy that saves a girl from a car

Adventure awaits 12 year old Brendan who must fight Vikings and a serpent god to find a crystal and complete the legendary Book of Kells. In order to finish Brother Aiden's book, Brendan must overcome his deepest fears on a secret quest that will take him beyond the abbey walls and into the enchanted forest where dangerous mythical creatures hide. Will Brendan succeed in his quest?