Stand up and walk. Keep moving forward. You've got two good legs. So get up and use them. You're strong enough to make your own path - Edward Elric.
FMA Brotherhood tells us the story of two brothers: Edward and Alphonse. They wanted so bad to return their mother's life that they used a forbidden alchemy technique in attempt to bring her back to life. Alchemy is the scientific technique of understanding the structure of matter, decomposing it, and then reconstructing it. It's based on the principle that only one thing can be created from something else of a certain mass: The Principle of Equivalent Exchange. The cost for attempting to revive their mother was losing their bodies parcially or completely. That said, the brothers' journey for recovering their bodies using alchemy starts, having plenty of events surrounding it.
So yeah, it's pretty much a shounen anime in essence. However, Hiromu Arakawa (the authoress) revealed a complex plot, with action, comedy and drama all in the measure to bring us a well balanced plot. The story takes place in Amestris, a country that in the past was the scene of a terrible civil war that almost ended the Ishibalian race. The show is full of conspiracies and terrifying hypotheses involving alchemy and politics, all well tied with extremely captivating characters.
The characters are all great. It's amazing how a show having a large cast was able to handle it with such excellence. Ed and Alphonse stand out as one of the best pairs in shounen with their great strong motives and deeply personal bond. The support cast shines as well. Mustang and Hawkeye relationship is always fun, Scar is a highly intriguing complex villain, Hohenheim with his mysterious background and personality is really captivating, the Armstrongs are great, so as teacher Izumi. I thought Winry would be the kind of boring useless character, judging by past experience with shounen, but I was pleasantly surprised. Everyone has a purpose, fitting very well into the story.
The anime shows us the various weaknesses of humankind concerning how we struggle to live inside a society in contrast to our ego and selfish desires. Humans should have a minimum of empathy for things to work out, since even the things we least imagine can be connected. If we become corrupt, it may be disastrous. We are just humans. We can't live without consequences, as the alchemy's principle states. Plus, it has a meaningful message to take away about the cost of gain and the meaning of perseverance. It's like Ed says:
A lesson without pain is meaningless. That's because no one can gain without sacrificing something. But by enduring that pain and overcoming it, he shall obtain a powerful, unmatched heart. A fullmetal heart.
In addition to a fluid animation and a great soundtrack, FMA Brotherhood stands out in every area. I wouldn't say it's perfect though, since the first episode is not a good introduction and the main antagonist should get more attention, but its qualities definitely obfuscates its flaws.
