Fullmetal Alchemist: Brotherhood

As kids, Edward and Alphonse tried to use alchemy to resurrect their dead mother. It failed in the worst way: Ed lost an arm and a leg, Al lost his entire body and now lives bound to a suit of armor. They set out to get their bodies back, and the search drags them into a national conspiracy that goes all the way to the founding of their country. This is the adaptation that follows the manga to its real end, so the early monster-of-the-week stretch is actually laying groundwork for a single tight story about debt, what you owe for what you take, and who built the machine you live inside.