S.T.A.L.K.E.R.: Clear Sky

S.T.A.L.K.E.R.: Clear Sky (Ukrainian: S.T.A.L.K.E.R.: Чисте небо) is a 2008 first-person shooter survival horror video game with role-playing elements. It was developed by GSC Game World and published by Deep Silver as a prequel to S.T.A.L.K.E.R.: Shadow of Chernobyl.

The player assumes the identity of Scar, a mercenary tasked with stopping a group of Stalkers from reaching the center of the Chernobyl exclusion zone, a forbidden territory surrounding the Chernobyl Nuclear Power Plant. The game uses much of the same regions as Shadow of Chernobyl, while introducing several new areas such as the abandoned town of Limansk. S.T.A.L.K.E.R.: Clear Sky introduces features to the series, including the ability to customize weapon and armor, as well as participate in faction wars.

A third game, S.T.A.L.K.E.R.: Call of Pripyat was released in 2009 as a sequel to Shadow of Chernobyl.