It is the near future.
The nations of the world have conglomerated into massive collections of like-minded peoples. Europe has become the neo-fascist state of New Balduria, the Middle East the Holy Impire of Islam, and North America is now the United Republics of North America, joining Canada, the United States and Mexico into one governing body. As the conglomeration continues, the world slowly turns away from the horror of nuclear holocaust and looks towards peace and prosperity.
But not everyone is ready and willing to forgive and forget.
On the fringes of the Holy Impire of Islam several radical and outlawed factions rise up, still full of the bitterness and anger that plagued the Arab nations in the late 21st and 22nd Centuries. They vow that the Great Infidel, the United Republics of North America, or URNA, will pay for the sins they have caused the world to commit.
In a daring raid, terrorists from the SJL or Sword of Justice and Light faction slip into the former republic of Kazakhstan and into a broken-down nuclear storage facility. There they manage to activate three of the weapons, now lying in mouldering heaps. And once they are activated, the SJL operatives launch them: one towards the capital of URNA, another at the capital of the Impire and the last at the New Baldurian capital.
While URNA, the Impire and New Balduria have long since mothballed their nuclear arsenals, they didn't deactivate the early warning detection networks they had spread across the globe and into low orbit. The three incomming weapons are detected and mothballed nuclear weapons are abruptly reactivated as an automated retaliatory response is launched.
The Benevolent Union of Asia, the Pan-Pacific Protectorate and the Republic of Northern Africa in turn detect those launches and further counterstrikes are launched. And within minutes, as the horrified members of these nations look on, the world is engulfed in the very nuclear holocaust they had tried so hard to avoid. Modern civilization dies in an orgy of radioactive particles sleeting through the atmosphere.
Dependent on Earth bases for their supplies and oxygen, the orbital stations, lunar bases and the Mars outpost also wither and die after watching their future demise appear in the form of mushroom clouds sprouting like weeds across the once-green face of Earth.
Yet, not all is lost. In a last ditch effort, members of several nations manage to make it into a series of underground facilities created by URNA and the human race is preserved.
A thousand years pass, Humanity deep within the bosom of the Earth barely managing to survive on the supplies they brought with them. Only the creation of the tyrannical Society allows the remnants of the once mighty race to survive deep in the bowels of the planet while above them the nuclear winter rages on and on.
However, even greater than the power of the atom is the strength and endurance of Nature. Despite Humanity's unwitting assault, she returns to full force as the nuclear winter eases its grip after the long centuries. And on the face of the broken world, she brings new plant and animal species. And new intelligences.
Out of the ruins of an URNA scientific experiment where various predator species across the planet were used to create new labor species with rudimentary intelligences, the Fisted Races arise. The fog of nuclear fallout completes the changes the URNA scientists began and now fully sentient, the Fisted Races look upon their new domain as their fledgling civilizations grow and strengthen. And in that growth, they quickly find themselves fighting each other in a struggle for domination and for the few natural resources left on the surface.
Into this battlefield Humanity returns, seeking the surface after a thousand years, their supplies finally exhausted. Thousands are slaughtered in the first atttacks before Humanity manages to use the last of its technology to create Gideon, a fortress state in the northern reaches of Noranda, which is the broken remnant of the North American continent.
There the Society collapses as Humanity returns to its warrior ways in a bid to survive against races that remember the oppression, the degradation and the slaughter Humanity had forced upon them when they were Masters of the Earth.
Several decades more pass, with Gideon barely holding on by the skin of its teeth against the onslaught. Then, at long last, with the final vestiges of their modern technology gone and a new, warrior-led society guiding them, Humanity carves out a niche against the warring Fisted Races and relative peace descends. That is, until now.