From the introduction:
The Fallout Universe, inspired the series of Fallout video games, is an exploration of America after a nuclear apocalypse brings the world to its knees. Despite the complete and total decimation of society, humans continue to fight for survival in this new and hazardous world.
To understand what the world became, you must first realize what the world came from. The Fallout universe takes place in an alternate timeline for the one we are familiar with in the real world. This timeline starts to branch off near the close of World War II. Communism thrives and fails to collapse heading into the 21st century, and its threat on free market economy grows deeper than ever. The world’s resources continued to dwindle, causing polarizing political conflicts that fracture alliances and strains international relations.
Despite it all, technology continues to advance aggressively. Incredible advancements are made in technology and robotics, while maintaining a real world 1950s aesthetic. Soldiers become equipped with laser rifles, plasma grenades, and suits of highly advanced powered combat armor. Robots become so mainstream that they are used for all purposes, from frontline combat to janitorial duties and child rearing. Technology becomes powered by miniaturized fusion technology rather than the world’s rapidly depleting oil reservoirs.
This shortage of oil provokes the communist Chinese government to invade Alaska for its resources in the year 2066. Alaska becomes a war zone between China and the United States, as the two powerhouse nations begin a back and forth struggle of decimating each other’s nation.
At this point, the signs are pointing to the end of mankind. Many begin to take steps for the annihilation of the world. Most notably, a massive series of underground vaults are established across the United States. These bunkers are intended to take a population of individuals and keep them and their descendants safe underground throughout a nuclear apocalypse. Designed to last for many generations, these vaults are designed for the long term survival of mankind.
In the morning hours of October 23, 2077, the Great War reaches its climax. The United States, China, and many other nations release their nuclear payload on each other. Within hours, the entire world becomes a devastated, irradiated wasteland. Contemporary society as it was ceases to exist. It was to be the end of mankind.