Recently we sent a group to Yantar. Unfortunately, nobody from the group returned. I was informed that they saw a few zombified stalkers from the group not far from the mobile lab of the scientists at Yantar. We can't allow them to remain in that horrible state. Your assignment: find and destroy that, which they've become.
Personal Notes
This mission requires you to kill a zombified stalkers in Yantar; he's got friends, though, so he won't be alone... which makes me wonder - how does zombied make friends, anyway? Ah, they share brains I guess! The mission seems to be given to you automatically when you enter Yantar.