Fullmetal Alchemist's summary

In an alchemical transmutation gone wrong, Edward Elric lost his right arm and his left leg, and his brother Alphonse lost his entire body, ending up as nothing but a soul in an empty suit of armor.

Equipped with mechanical "automail" limbs, Edward becomes a state alchemist of the military and starts a long journey across the nation of Amestris along with his brother, trying to restore their bodies to their original shape by finding the so-called Philosopher's Stone, which is said to give an alchemist the ability to overlook the law of Equivalent Exchange.

At first the Elric brothers have that one goal in mind, however, as their journey continues they find themselves fighting for something that is much, much greater than they could have ever imagined.

Story in Fullmetal Alchemist: Brotherhood
Fullmetal Alchemist: Brotherhood begins with the story of Isaac the Freezer, a former State Alchemist bent on destroying the reign of the Fuhrer. All the familiar faces have returned, including Winry, the unofficial engineer and lifelong friend of the Elric brothers, as well as all the brothers’ old friends from the military, such as Lieutenant Hughes and Colonel Mustang.

While it is extremely interesting to see this slightly different take on the manga, so far the series has been fairly disappointing in terms of developing new insight into the adventures of the Elric brothers. Instead of deepening the characters by delving into their escapades not shown in the original series, the new series is almost an exact copy of the original. Apart from the first episode, every concurrent episode seems to be a re-hash of the original with only slight deviations.

Halfway through the series, however, viewers should expect a great deviation from the story told in the original series. The original tv show passed the manga in and created a different story arc than the manga, Brotherhood will follow the story arc of the manga series, meaning a different ending than that found in the original series.