The year is 2030. War had broken out among the World in 2021, started a biochemical trend in 2023, then turned nuclear in 2028. Mutually assured destruction has caused the surface of the American land to become nothing more than a pockmarked toxic wasteland extending even into the southern parts of Canada and the northern parts of Mexico. The lingering effects of biochemical warfare- a long-acting virus now present in most people's blood- makes things even worse.
Now, after the war, certain places are still safe for humans without specialized apparatus, but mutated and infected creatures- animals and humans alike- roam the land. Outside communication is impossible.
Society is in shambles, there are few survivors and even fewer nice ones. Bands of pillagers roam the land, taking what they want and need from hapless wanderers or struggling settlers and often killing them or forcing them to join their ranks. Often times, well-established settlements are suspicious of outsiders and shun them unless they have something incredibly useful to offer.
Animals affected by both the virus and the waste are stronger, larger, faster, and more aggressive than their normal counterparts, and often attack anything that moves.