After Norwegian researchers discover an alien ship buried in the ice, paleontologist Kate Lloyd (Mary Elizabeth Winstead) joins the team at the isolated Arctic outpost to investigate. She finds an organism that appears to have perished in the crash eons ago but, in fact, is about to awake. Freed from its icy prison, the insidious life-form goes on the attack. Paranoia spreads like wildfire among the crew as they fight to survive against a creature that assumes the shapes of its victims.