Today GSC Game World announced a prequel to this year's first-person shooter, S.T.A.L.K.E.R. Subtitled Clear Sky, the origin story turns back time one year before the first game, 2010. Set in the heart of the Zone (the Chernobyl Nuclear Power Plant) where a catastrophe has destroyed all safe modes of passage, the stalkers are starting to become isolated in the dangerous territory. But new areas have been discovered, and these patches may provide the answers needed to stop this disaster.

The traumatic circumstances are sparking tensions between the stalkers. Groups are vying for control of the newly discovered territories. It's every stalker for him/herself as the Faction War erupts.

The game's protagonist is a mercenary named Strelok who holds no allegiances to any group -- yet. Players must choose a side and lead that faction to victory.

New areas are waiting to be explored, including Red Forest, Limansk, and the Pripyat Undergrounds. The NPC AI has apparently been improved, and they will avoid obstacles and can now use grenades.

S.T.A.L.K.E.R.: Clear Sky is set for a Q1 2008 release.