Fullmetal Alchemist is one of the best animes I have ever seen. It can make you crack up laughing and sob within a few episodes. There are some character I see on screen and instantly want to cry because of how tragic their stories are. With others I am glad they got what they deserved and a few that ended up truly happy.
I guess what I'm trying to say is that it's an emotional ride so, prepare yourself.
The show is centered around two brothers, Edward and Alphonse Elric. Edward is the elder of the two and shoulders all the responsibility for what happened to them and he spends every moment of his life trying to fix it.