THe game is based 200 years into the futur within the ruins of DC after a nuclier war,from the music and structers, id say the war took place during an alternet 1950-1960 that included robots and such. The main objective for you character is to escape the lie filled underground shelter known as vault 101 and enter the Capital Wastland (once DC) to find your father, but you can take on small quests and just screw around for as long as you like.
I bought the game, its fun, but it'd be wise to take advanteage of the saving feature, I've had to restart twice due to my tendency to kill a few friendlies here and there just to see if I could get away with it and shit like that.
I suck at spelling >_>