Fallout 3 is set in a dystopian future in which a nuclear war devastated most of the planet, the player plays as one of the survivors that was born in a system of vaults which were built to outlast the nuclear fallout.
During the gameplay the awe for technology and Artificial Intelligence is presented as a religion of sorts, combining features of older technology which has existed in human history, as well as fictional technology which has been fueled by the nuclear warfare.