You live in Vault 101, a bunker designed to keep its occupants alive through the nuclear war that ravaged the surface. It's a cleverly veiled character creation and tutorial sequence that sets the backdrop of the story. The game begins with your birth and then quickly moves through childhood with snapshots of pivotal events, such as the day you get your Pip-Boy 3000.
It's a world that is both fantastic and somehow believable. A nuclear war has taken away most of these technological comforts, providing the backdrop for a game with a dreary, desperate atmosphere filled with glib and dark humor. It's a quaint sci-fi view of a future filled with atomic cars, robot servants, and incredibly basic computer terminals. if several thousand nuclear bombs were dropped on it. It exists in what people on the cusp of the atomic revolution in the 1950s saw as the sci-fi world of tomorrow. The Fallout universe paints a picture of a dystopian future.