STALKER: Clear Sky is set in 2011, one year prior to the events of the original STALKER game. In it, a group of stalkers reaches the heart of the Zone (the Chernobyl nuclear power plant) and triggers a cataclysm. An immense blast of anomalous energy transforms the Zone, and the once reliable and relatively safe roads are no longer so. The landscape is wiped clean, and previously unknown areas appear on the Zone map. Stalkers and expeditions perish or end up isolated within the lost territories.

The protagonist is a mercenary who appeared at the edge of the opposition between stalker factions, Strelok and the Zone. The main character experiences the events that led to the creation of the Zone right up to the point from which the original STALKER game begins. STALKER: Clear Sky is now available for pre-purchase on Steam at a 10 percent discount until its September 15 release.