A Norwegian chopper circles the perimeter of United States National Science Institute, station 4, a remote scientific outpost deep in the Arctic. For reasons unknown, a gunman inside the chopper fires a rifle at a dog. The engagement ends with the chopper down and the two-man crew killed. The confused American research team takes in the seemingly harmless dog, and several of the group, including R.J. "Mac" MacReady (Kurt Russell, Stargate), take their own chopper to the Norwegian outpost in hopes of discovering what drove the Norwegians to hunt the dog in such an aggressive manner that ultimately cost them their lives. There, amidst the smoldering remains of the station, they find the remnants of some "thing." Taking it back to station 4, the facility's medical examiner, Dr. Blair (Wilford Brimley, The Natural), finds inside of it normal human organs, but the "thing's" external appearance is anything but, a bloody jumble of limbs, torsos, and faces melded together as one. Soon after, the team discovers a deadly creature in their midst, one that can absorb and imitate any life form it so chooses, leaving the team confused, frightened, and untrusting of one another. A series of bloody events reveals that appearances can be deceiving, that your best friend may very well be harboring inside of him a deadly creature capable of unleashing unspeakable, grotesque attacks.