In 2015, the rotting plague killed a quarter of humanity and shattered the existing social, economic, and governmental orders. Famine, civil strife, and outright warfare followed (killing another third of humanity, or more). A scant decade later, and the survivors were banding together, striving to restore order, when the Emergence began.
There is another world beyond ours, a world of magic and power. Vortexes connecting our world to the Beyond opened up, and out them came monsters, refugees, and magic itself. And in the middle of the Atlantic, a single vortex of immense size disgorged the ancient and uninhabited island of Atlantis.
All across the world, magic now worked. All across the world, monsters Emerged from the vortexes. And all across the world, the Beyonder races sought shelter from the evil consuming their homelands.
It is 2039, and the United States has been shattered. The government controls but small portions of the country.
The rest is “The Outlaw”, places and people beyond the control of the government. The Outlaw is a chaotic place where people fend for themselves. No safety net, no police, no government save for what people make themselves.
There are dangers here. Bandits, thieves, and murderers. Bloodgangs, packs of vampires or ghouls that hunt humans for food and sport. And Emerged creatures, nightmarish and powerful.
Then there are the Guns. Freelance lawmen (or vigilantes), heroes (or thugs), and killers. Always killers.
When people need protection, when they need revenge, when they need a monster hunted and killed, they hire Guns. Some work for the wealthy, some even the State, others work for the dispossessed and powerless.
They are assassins, mercenaries, freelance lawmen, bounty hunters, and, yes, even criminals. Sometimes there is but a sliver of difference between the marauders who rape, kill, and steal, and the Guns who hunt them.
In post-Emergence America, Guns are the heroes and villains of the Outlaw.