Stuck in Germany, Edward Elric is more or less forced to live his life with Alfons Heidrich, a near spitting image of his little brother, Alphonse Elric, whom he has since been separated from. As time goes on, Alfons becomes less and less of a replacement, and more and more of a person, until finally, Edward can become accustomed to his new life in a new world.
And regardless of if the Elric likes it or not, the world continues changing just like before, only this time, a different person is by his side, helping him along the way.