From the introduction: Fallout centers around a post-apocalyptic retro-future America. The tone of the setting is a cross between post-apocalypse-survival and 50s-era-atompunk. After World War II, the world advances the power of the atom, and uses up many of its natural resources in the process to create a variety of fusion powered comforts. When resources begin to run dry, hostilities around the world escalate, resulting in a catastrophic nuclear war. Some people managed to survive in the blasted wasteland of Post-war Earth, but others survived by paying for space in large underground Vaults constructed before the Cataclysm, Vaults built by an American corporation called “Vault-Tec”.