A long time ago there was magic. Magic was used to help people and to make their lives better. However, magic was difficult to master, and once people discovered technology which was easier, they forgot about magic.
This feels like a world that could have been much more explored, but the movie plays it safe by having all the characters be no different than modern boring humans. However, that is part of the point, since this is a culture that has lost its heritage. The movie holds a surprise for us, because what seems on the surface like a three-star film, delivers in a big way with a four-star ending. This is by no means the best Pixar film, but Pixar can still work a magic of their own.
Our two main characters, both elves and both brothers, go on a quest to find something magical that will bring back their long-deceased father just for a day so that they meet him. As a result, they discover more about themselves and help their culture regain some of what it lost.
Rating: B+. I would love to see a sequel where they better explore this world.
P.S. There is much stuff in the trailer that didn't make it into the movie. This happens sometimes when a movie undergoes many revisions before being released.