Equestria finds itself once more host to a human. This one is named Artyom, and he's a long way from home. A very long way. But he seeks a new life here. And while his heroic actions should speak for themselves, he would never be self-confident enough to believe it.
Spoilers for Metro 2033 and Metro Last Light. All knowledge and references come from the videogames, I will confess that I haven't gotten around to the book QUITE yet.