After a devastating global nuclear exchange in 2077, known as the Great War, much the surviving population retreated into the large subway systems throughout the Commonwealth, which were capable of shielding their inhabitants from the radiation like a fallout shelter. Sometime after the initial bombing, animals and humans alike became horribly mutated and began to roam the icy, highly irradiated wasteland. Massive hoards of feral ghouls eventually found their way into the metro, terrorizing the residents of the stations that had become small settlements.

In 2082, the surface has begun to normalize, but only in appearance. The ice has begun to melt, and the sun can occasionally be seen, not to mention the occasional downpour of rain. Mutated wildlife and feral ghouls still pose a significant threat, and the air is still highly irradiated, requiring humans to wear gas masks at all times during ventures to the surface to prevent lethal radiation poisoning.

Even after the Great War annihilated every civilization on the planet, surviving soldiers of the United States Army still occupy and maintain several military bases. Rumors have it that these soldiers follow the orders of an entity known as the Enclave, the last remnant of the United States government. While their goals are unclear, Army Remnants present an extreme threat to all survivors who wander into their territory, as they have orders to shoot all survivors on sight.

Nuclear Winter Edit

The cause of the nuclear winter coating the planet it most likely had to do with the massive dust clouds caused by the nuclear blasts which were thick enough to block out the sun. Because the warmth and light of the sun is barely able to penetrate this dust cloud, it has caused freezing conditions within the Commonwealth, and likely the rest of the planet. This harsh winter diminished almost all hope for human life above the ground, and most wildlife left on the surface became mutated to cope with the extreme conditions. It is unknown how long the nuclear winter may last, but by 2082, the frost is slowly melting and the ambient temperature is steadily increasing.

Nuclear Spring Edit

The nuclear spring is the result of the steady increase in temperature as the dust clouds recede, allowing the snow and ice to melt. An occasional sun can be seen through the clouds and rain can be felt for the first time in decades. However, this rain is not pure or harmless, as it is in fact lethally irradiated (possibly acid) rain. The rain droplets have become saturated with irradiated and toxic ash from the nuclear clouds, and in turn are pitch black, blackening the surface with irradiated soot every time it rains. It burns the skin and no matter the equipment, death will occur in only a matter of minutes - although a gas mask may delay this process.