S.T.A.L.K.E.R.: Shadow of the Zone

Crow, a freelance stalker, takes a job at the Cordon guiding a mercenary crew into the heart of the Zone after a strange radio broadcast. Among them is Brain, a nervous tech specialist well out of his depth. A skirmish with a Monolith patrol sets the tone early, and soon Crow begins seeing something in the treeline that speaks to him. What the signal does to the people who hear it turns out to be the real threat.