Intricately animated Irish fantasy about how the Book of Kells, an illuminated medieval manuscript, came to be. Young novice Brendan lives in the abbey of Kells, Ireland in the 9th century where he helps the monks illustrate the gospels. The abbey is in peril from Viking raiders and Brendan is not allowed outside the walls, especially not into the supposedly haunted forest. But when refugee monk Aidan needs certain berries for ink, Brendan willingly travels into the forest to fetch them and encounters various magical creatures along the way.