Somewhere in the depths of space is a coalition of aliens who are completely and unreasonably mad at a city on Earth. It’s hard to say why this is, whether that be a stray parking ticket or someone there drinking their koks without frapping it, but whatever it may have been that city’s got to go. The aliens won’t stop escalating their attacks until its shield is down and the city is wiped from the universe for good, taking all of humanity with it in one final massive explosion. It would probably be a little easier for them, though, if the city wasn’t defended not only by its shield but a massive gun capable of nearly-overwhelming firepower.