As a prequel, Clear Sky will include a storyline which explains a little more about Strelok's past, and how he ended up in the back of that truck with a gaping hole in his memory. This time, however, you are in a somewhat different world. Blowouts from the reactor keep the Zone in flux, as project lead Anton Bolshakov explains: "The blowout in the story changed certain areas of the Zone, so the anomalous activity in certain areas faded, and increased in other areas. Paths to the known locations have disappeared, while others have opened up. Part of the old areas will be preserved, while there will also be new ones too. Right now Pripyat will not be part of Clear Sky, but we'll see how things go."
While the exclusion of the abandoned city might be a disappointment for the STALKER hardcore who wanted to see it made explorable, the allure of new tracts of Zone and new weird dereliction to explore are powerful. The open-ended possibilities for poking about in old ruins was one of the most appealing aspects of STALKER, and Clear Sky will provide plenty more of that.