Residents of the city of Pripyat were evacuated due to dangerous levels of radiation following the Chernobyl disaster.
The Soviet government established an exclusion zone around the Chernobyl nuclear plant, restricting access to the contaminated area.
The large concrete sarcophagus was completed to encase the damaged reactor and limit radioactive release.
The New Safe Confinement structure, designed to contain the reactor more effectively, was constructed and later moved over reactor 4.
A massive explosion occurs inside the Zone at the Chernobyl Nuclear Power Plant, causing an expansion and intensification of anomalies and mutants.
The Ukrainian army conducts an initial expedition into the Zone to reclaim control, but suffers heavy losses and complete lack of success due to unknown causes and environmental dangers.
Anomaly activity increases dramatically, making navigation hazardous and increasing mutant populations.
Major Alexander Degtyarev is assigned to investigate the mysterious disappearances of army helicopters within the Zone as part of a new military operation.
Degtyarev enters the Zone and searches for clues regarding the lost helicopters, encountering stalkers and hostile factions.
Degtyarev obtains information related to Strelok and the earlier expeditions, shedding light on the Zone's secrets.
Degtyarev encounters the Clear Sky faction and learns about the internal conflicts and agendas within the Zone.
Degtyarev explores the secret scientific labs of Yantar seeking evidence for the helicopter crash sites and anomalous activity.
Degtyarev discovers the fate of the army's missing helicopters and the cause of their mysterious disappearances.
Degtyarev engages hostile forces and anomalies in Pripyat to complete the mission and secure the remaining evidence about the Zone.
With the mission complete, Degtyarev is extracted from the Zone, marking the end of the expedition.
