“Humankind cannot gain anything without first giving something in return. To obtain, something of equal value must be lost. That is alchemy's first law of Equivalent Exchange.” Edward and Alphonse Elric, two teenagers able to use the Alchemy learned the hard truth.
If you still didn’t watch the excellent and renowned Fullmetal Alchemist: Brotherhood (FMAB), this is to me a must-watch! The anime mixes science through Alchemy, magic, action, adventure and fun in a European Industrial Revolution look-alike world. It might even make you shed some tears. Pay attention though, FMAB follows way more strictly the original manga while his older brother Fullmetal Alchemist does not really.
So for those who have never seen it, go for it!