I've downloaded through episode 27 but have only watched through about episode 8. It's basically about two kids whose father left them in wartime, and later on their mother dies. The two kids are trained in alchemy and decide that they should try and bring their mother back from the dead. Alchemy with human subjects is forbidden and things go awry so the younger brother loses his body (so his older brother attaches his soul to a suit of armor) and the older brother loses his arm and leg which is later replaced with auto mail.
The show, as far as I've watched, is about them searching for a way to give the younger brother a body again.
I think it's pretty good stuff. The characters are interesting and uses of alchemy are original. Definitely worth checking out if you've got the time.