In the icy isolation of Antarctica, a group of American research scientists is disturbed by the unexpected arrival of a seemingly crazed Norwegian helicopter pilot intent on shooting a dog escaping across the snow. After the encounter leads to a deadly mishap with the Norwegians, the bewildered Americans take in the dog, unknowingly inviting a malevolent force into their midst. As night falls and the cold deepens, the team discovers the charred remains of a Norwegian research station, unveiling evidence of a strange discovery and a horrific fate that befell its occupants.

As the team assimilates these unsettling clues, the true horror reveals itself: the creature they have brought back is an alien life form capable of assuming the appearance of anything it kills, including humans. Paranoia sets in with the realization that any one of them could be the alien in disguise. The scientists, led by the helicopter pilot MacReady, must navigate a taut and terrifying battle against an unknown enemy, where trust is a luxury none of them can afford. Cut off from the world and under the constant threat of annihilation, survival hinges on identifying and destroying the shape-shifting predator before it can escape and spread to civilization.