The basic plot: towns/villages are being ransacked by Vikings in search of gold. One of the towns attacked is that of Iona, home of the legendary Book of Iona. One of the abbots (Aidan) who was working on the book managed to escape with his life, the book, and his pet cat. Aidan arrives at Kells, where he continues to work on the book. Meanwhile, the inhabiitants of Kells work on the town wall, attempting to establish protection against the impending invasion of the Vikings. The story focuses on the young character of Brendan, who is the nephew of abbot Cellach, the town's leader. Brendan is fascinated by Aidan and the book of Iona, but also tries to honor the rules and requests of his uncle (there's a bit of a conflict between the two). During the process of learning more about the book, Brendan meets and establishes a friendship with a forest fairy (Aisling) who is the protector of her forest.
Brendan's conflict of learning more about the book, or following the order of his uncle, embodies the larger conflict of the town: is faith or might more important? Aidan places importance on finishing the book, while Cellach places importance on finishing the town wall. As Aidan and Cellach talk, Cellach says "it is with the strength of our walls that they will come to trust the strength of our faith." But much of their faith is influenced/tied to the book. So if the book is not finished, then what is protecting their faith? Of course, if the town is not protected, then there will be no one to complete the book. But still, as they talk, you can't help but feel like the Aidan is right and that Cellach is focusing too much on just the wall. Cellach's focus is intensified by the setting in his tower. The tower room is covered with designs of the town and the wall. It is part beauty, part meticulous planning, and part overwhelming obsession.
I originally saw this movie a couple years ago. I remembered that I liked it, but I had forgotten just how much I enjoyed the visual style and how gorgeous I think it is! The animation has a very classic/gothic style, very clearly drawing inspiration from early Celtic art and literature, while still having a fresh take on it. Much in the same way that some movies based on graphic novels try to emulate the visual style of the surce material, while still trying to put a unique spin on it. I should note that I'm not actually sure if this movie is drawing off of any specific source material, or just Celtic art in general. Either way, I loved the visual style and I think that it was the strongest aspect of the film. Some of the scenes were so intricate that they conveyed much more about the characters than the characters themselves, such as the tower scene mentioned above. And The use of repeated visual themes (primarily circular patterns) helped to establish a connection between the town and the forest, illustrating that they were both experiencing very similar situations (Aisling did not want the townspeople destroying her land).
The visuals were definitely the strong point (practically every frame, especially in the forest, was a work of art), but the music is pretty solid as well, helping to establish and maintain the setting in each scene. In fact, I wouldn't be surprised if the visuals and the musical score were the creative force driving the production of the film, with the story and dialogue added in to tie it all together. There were some highlights of the story (the fairy is delightfully quirky, but with an air of mysterious danger about her. The interaction between childlike curiosity and aged wisdom. Aidan's lovable cat. The delicate balance of power and knowledge between good and evil), but overall I felt like the story and the voice acting were the weakest parts of the film. They weren't entirely bad (the voice actors of the main characters were good), but they definitely could have been developed more to make a much more solid film. But the story and the acting aren't really why I felt this movie was worthy of a repeated viewing. It's the visuals, aided by the constant soundtrack, that make it so enjoyable to watch.
Recommendation: it's worth a rent. If you appreciate art and/animation, you'll enjoy the stylized visuals. I enjoyed the visuals enough for a second viewing, and will probably watch it again in the future. But the somewhat underdeveloped story (it kind of feels like they got tired of writing towards the end and just skipped to the ending), and some pretty poor voice acting from some of the minor characters keep me from suggesting that you add it to the top of your queue. Aside from a few scenes that might be upsetting to kids (when the Vikings attack), it's very family friendly. So if you're running out of movie options to watch with the entire family, and you want something a bit more visually unique, give this one a shot.