The story of S.T.A.L.K.E.R.: Clear Sky brings the players one year prior to the events of the original S.T.A.L.K.E.R. game in 2011. A group of stalkers has for the first time reached the very heart of the Zone - Chernobyl Nuclear Power Plant, and brings about a cataclysm on the brink of a catastrophe;An immense blowout of anomalous energy changes the zone;There are no more reliable and relatively safe roads;The entire levels vanish in the outbursts of anomalies;Stalkers and even expeditions die or end up sealed lost on the territories;New areas, which remained unknown since the time of the Zone emergence, appear on the Zone map;The Zone continues to shake with blowouts;The Zone is unstable;The anomalous activity is at it's maximum.
Changes of the Zone map known to stalkers shake the fragile balance of forces in the Zone;Among the groupings, there flare up hostilities for the new territories, artifact fields and spheres of influence;There are no more old enemies or friends - now everyone is for himself;The Factions War has started between the groupings.
