Neverwinter Nights (NWN) is primarily a Fantasy Role Playing (RP) game with considerable depth and may be as complex as you wish to make it. The "land" the game is set in is called Edon, and is not directly associated with any existing literature. While you can participate at any level you wish, the overall thrust of the game is that the war between the Underdark and the Surface has dwindled, and a tentative truce has been made, although it is not followed by all, by any means. In the meantime, Edon is threatened by a race of strange demons known as the Scourge, whose apparent purpose is to destroy life in the lands.