The events of the game unfold in an alternative fictional universe of S.T.A.L.K.E.R. of our time on the territory of the Chernobyl Exclusion Zone, where people have recently begun to arrive, experiencing an irresistible urge to find an artifact that appears to them in their dreams.

In the "Zone" there is a constant armed conflict between two main groups. "Stalkers" are researchers, adventurers, treasure hunters. "Bandits" are criminals, marginals who fled to the "Zone" from justice and / or for the sake of monetary gain. Due to the constant influx of new people, new groups begin to gain strength: "Blessed" - obsessed with the desire for the mysterious artifact "Blue Ball" and "Orderlies" - opposing the blessed, extremely cruel radicals who accept only the laws of force, adherents of the idea of ​​​​supremacism and their superiority over the blessed.

There are also large official organizations in the Zone that deal with more global matters. "Frontier" is an association of experienced military men and stalkers. Their goal is the complete destruction of all mutants in the Zone and the salvation of humanity as a whole. "Zarya" is an organization of anarchist researchers who believe that the Zone cannot have owners and that it should be used to its fullest potential. There are also smaller official organizations. "Mercenaries" who carry out various orders, and "Covenant".

The player takes on the role of a blessed newcomer to the Zone who must unravel the mysteries of the Zone and find the mysterious "Blue Ball".