Dungeon Keeper 2 is a strategy game developed by Bullfrog Productions and published by Electronic Arts in 1999 for Microsoft Windows. It was released in Europe and North America in June 1999. It was the sequel to Peter Molyneux's Dungeon Keeper and predecessor to the canceled Dungeon Keeper 3. Molyneux did not have an active role in the creation of the Dungeon Keeper 2, though many of his ideas lived on from the previous game. Like its predecessor, players take the role of a dungeon keeper, building and defending an underground dungeon from the would-be heroes that invade it, as well as from other keepers. In the game's campaign mode, the player is charged with recovering the portal gems from each area in order to open a portal to the surface. This was charged as a setup for the sequel, where the gems would be used to invade the surface world and defeat the faction of goodly heroes.
Source: Wikipedia, "Dungeon Keeper 2," available under the CC-BY-SA License.