Now about the story: it's a prince from a smal tribe who gets hurt by a demon and thus has to leave his village. He tries to find out why the boar became a demon and where the iron ball which was found inside him comes from. He then reaches the forest where the animal gods live and he also finds that there a iron town was built to make iron from the ore.
It's a very moving story and I love the way it's animated. It looks so real, but in the animated way. I don't love the "trying-to-copy-real-faces" type of animated films, cuz they never really manage to do that properly. And the score is extremely beautiful.
If you like animated Japanese films, you've surely seen this one, because it's one of the best. If you're not into animated Japanese (yet), watch this movie once, I'm sure you'll like it.