Let's get something straight: You need to see this film.
The storyline follows Brendan, a young boy growing up in the Abbey of Kells, under the supervision of his uncle, Abbot Cellach. The good Abbot is obsessed with building and fortifying a wall around the abbey that will save Kells from the Viking invaders, and he has ordered Brendan to stay within the abbey's confines.
Along comes Brother Aidan of Iona and his cat, Pangur Ban. Aidan has brought the illuminated text-in-progress, the Book of Iona, and apprentices Brendan, who must sneak out of the abbey to collect the materials to make the colorful inks. In the surrounding forest, Brendan befriends Aisling and battles a metaphysical sea serpent, Crom Cruach, neither of whom should exist by 8th century Christian standards (or today's, for that matter).
The storyline, good as it is, almost pales in comparison to the richness of the animation. It's stylistic interpretation of traditional Irish art and the frequent juxtaposition of three dimensional and two dimensional animation is simply stunning. In case you didn't get enough out of the trailer to see what I mean:
|Via (I know. It's blurry. Use your imagination.)|
I would not recommend it for young children. Besides a lot of the history and art and literary references going right over their heads, the Vikings are seriously scary...
Go. Watch it. And prepare to be transfixed.
Wikipedia film page
Wikipedia historical Book of Kells page (Worth a read just on its own.)
(True: The real Book of Kells is housed in Trinity College in Dublin. I went to Dublin once, but I arrived late in the evening and left early in the morning for a bus tour, and only got to see things that were both outside and well-lit. Which gives me an excuse to go back someday.)