Once you fire up the game, it takes very little time for you to be hurled headlong into 'Rapture', the world in which BioShock is set. The game begins with a brief introduction as to when and where you are (1960, in case you're wondering), but the next thing you know the plane upon which your character is travelling is plunged as a flaming wreck into the Mid-Atlantic. From here, it's a case of swimming for your life to the conveniently placed monolithic structure in the middle of the ocean - A building which leads to a door, which leads to a capsule, which leads deep under the sea... To Rapture, the creation of a man known as Andrew Ryan.

Like most huge underwater cities in science fiction, Rapture has been built as one man's utopia - A world for the brightest minds in science and art, and the hardest working men and women wishing to escape from the oppression of capitalism, religion, communism and the like. This freedom from the normal constraints of humanity has led to numerous scientific breakthroughs, giving the people of Rapture access to what are known as 'Plasmids' - Serum which can rewrite a person's genetic code to give them, to put it bluntly, super powers. Need to perform telekinesis, or shoot lighting from your hands? Buy yourself the relevant Plasmid, and enjoy your new abilities to your heart's content.