S.T.A.L.K.E.R. is a first-person shooter survival horror video game franchise developed by Ukrainian game developer GSC Game World. The series is set in an alternate version of the present-day Chernobyl Exclusion Zone in Ukraine, where, according to the series' backstory, a mysterious second Chernobyl disaster took place in 2006. As a result, the physical, chemical, and biological processes in the area were altered, spawning numerous nature-defying anomalies, artifacts, and mutants. The player takes the role of a "stalker" - a name given to trespassers and adventurers who have come to explore the exclusion zone and its strange phenomena.