After stumbling across a secured Ministry of Image lock room, three ponies discover a form of music long forgotten by the Great War. Now it's time for them to remind Equestria that once upon a time there were tunes that didn't just talk about the good old days. But the only audience that could really listen are a rowdy group of raiders. Music is gonna be the one line of defense they have, but at this point they have nothing left to lose.
This seems cool, I'm writing my own fallout crossover.