A group of Americans, visiting one of their brothers who is in Russia, decide to take the "Special Tour", which involves a former soldier who takes them in a van to the deserted city near the radioactive Chernobyl reactor. When they can't get limited access to the area because the road is blocked by Russian guards, the tour guide takes them in a back way, though he warns them that they have to leave before dark. They explore some of the abandoned buildings, are frightened by a big brown bear that's taken refuge there--and find out that the vehicle will not start. Which is a big problem since there some very unpleasant locals that are hungry...
It's along the lines of The Hills Have Eyes and any other mutant movie you've probably seen. But this is one of the better ones.