Dungeons & Dragons, in its purest form, consists of powerful heroes, a town, a dungeon, and a DM ready to thumb through the various monster books unleashing unusual horrors on the hapless characters. That's why the latest expansion pack for Bioware's ground-breaking Neverwinter Nights D&D simulator, Hordes of the Underdark, eschews travel across strange lands, sweeping interconnected adventures, and most importantly, artifact recovery. Essentially, it has more in common with the better player-created modules -- like those based on old school D&D -- than the original campaign or the recent Undrentide expansion.