Kris, Steven, and Dusty, three men... three brothers, not in blood, but in arms. They dont know where they are or how they got there, but they use their wits and and skills as American fighting men to help end a war, that is not their own.
Equestria is fighting her first World War after the 2nd Industrial revolution. She hasn't fought a war in a while. Before his death, Discord enlists the help of several creatures that are all too familiar with the concept.
Applejack has been raising humans on her farm since she was a filly, but never was she prepared for a mysterious human falling out of the skies. In order to protect him, she decides to adopt him as her own.