It's 1957 and the movie opens inside a Russian cargo plane flying over freezing airspace. Two Russian pilots are in the cockpit talking about the cargo they are carrying. The co-pilot comments that he will go to the cargo hold and take care of things saying it's now or never. The co-pilot enters the cargo hold where three other Russians are looking at American nude magazines and offers them a bottle of vodka. The camera lingers on a padlocked box in the cargo hold that they are using as a card table. Purposely dropping the bottle of vodka so his comrade is forced to bend over to pick it up, the co-pilot then quickly pulls a gun and shoots him in the head. A gunfight ensues between the co-pilot and the cargo hold Russians. In the middle of the gunfire, the pilot is shot and the plane begins to plummet. Eventually everyone is dead as the plan crashes into the ice of Antarctica.
Present Day. We see shots of the frozen desert of Antarctica. We follow a warmly clad figure through a heavily populated international research center. The figure walks past various scientists outside including a group of streakers. The figure enters the building and several scientists are clad in Hawaiian luau apparel, getting ready for the end of the season party. Everyone is packing up to leave the center before the six months of winter sets in. We see more shots of the center as the figure walks through to a bedroom.
In the bedroom, the figure begins to take of layers of protective clothing and we see that it is Carrie Stetko (Kate Beckinsale). Carrie undresses, hangs her US Marshall badge near her bed and climbs into a warm shower. While showering, Carrie's name is called. She leaves her shower, walks into her room, and is greeted by Doc (Tom Skerritt). They talk about the fact that everyone is leaving and that Carrie is giving up her post instead of wintering through again with the Doc. It's at this point that a discussion of a whiteout is first had and that in a whiteout you can't see more than six inches in front of your face and a person can freeze to death in seconds.
More random events follow as well as the revelation that a hurricane-style storm is rolling in and that the entire research facility will have to be evacuated. Carrie bumps into a towel-clad, just showered Russell Haden (Alex O'Loughlin) in the hall and Russell solicits a body search from Carrie. She comments that he was one of the streakers and based on what she saw, she's not interested. Carrie is informed by Shaun Doyle (Sam Murphy) that a body may have been discovered in a remote area. Carrie says she'll check it out.
Carrie and Doc hop on a plane flown by Delfy (Columbus Short) and fly to the location. Delfy is former military and has only been flying in Antarctica for a year. The plane lands and Carrie and Doc find a frozen body that looks like he fell from a cliff while climbing. They turn the body over and find a security badge identifying the body as McGuire, another scientist. They theorize that he fell while climbing but can't figure out why he was out in such a remote area. They take the body back to the lab.
Carrie and Doc wheel the frozen body through the middle of the luau, disgusting everyone they pass. They go into the medical facility and perform an autopsy. They notice that McGuire has a badly stitched wound on his leg with a distinctive loop at the top of the thread. They also can see that he has been stabbed in the chest by an axe, which leads Carrie to believe that there is a murderer on the loose. She says she will have to investigate.
Carrie reviews logs of science groups and determines that McGuire belonged to a group of three scientists including Mooney (Steve Lucescu) and Rubin (Jesse Todd). The three of them were looking for meteorites. Carries attempts to contact the remaining scientists and manages to reach Mooney who asks that she come to Vostock (an old Russian station) and Carrie obliges.
Carrie and Delfy fly to Vostock. They search the Cold War era facility and find no one. Carrie says that she will need to check one last building and dresses in her extreme weather clothes. As she opens the door to go outside, her coffee falls off a bench and immediately freezes. Carries clips herself into a safety rope system and heads to the out building. She enters the building and takes off her gloves. She walks into a room and sees Mooney lying on a couch. She walks up to the couch and Mooney is gushing blood from a neck wound. Suddenly, a black-clad killer appears behind Carrie. She dodges the killer's axe and runs out of the building and back outside. She clips herself into the safety line, but the killer follows, also clipping himself in. He continues to swing his axe at Carrie, but Carrie manages to evade him. When Carrie gets to the door, she turns the metal handle without her gloves and her fingers stick to the handle, pulling off her skin. She makes it inside and manages to keep the killer out and then passes out.
Carrie has a feverish dream of her time as an agent in Miami where she and her partner had brought in a suspect. Her partner tells her to take a nap and the scene forwards to her washing up at a basin where the suspect attacks her and she screams for her partners help but no avail. She wakes to Delfy at her bedside catching her flailing arms. They rehash the attack and Carrie decides to go back to the outbuilding. They get there and see Robert Pryce (Gabriel Macht), a UN security agent. Pryce is examining Moody's body and he and Carrie square off. Carrie doesn't trust him but they agree to take the body back to the facility together. At the facility, they conclude that the third party in the research group, Rubin, is missing and must be the killer. They decided to head out to the groups most recent research site.
Carrie, Pryce, and Delfy climb into a Caterpillar snow vehicle and head to the science groups last know research grid via GPS. At the grid, Carrie notices that the ice has been worked and begins to walk around. She suddenly falls through the ice. She looks around and sees a trail of blood on the wall and the door to the Russian cargo plane. Delfy and Pryce climb down by rope and they all enter the plane. They begin to look around and Carrie figures out how the gunfight took place. They notice the locked box has been opened by a large crowbar and six cylinders removed. This is how McGuire cut his leg that he later stitched up. Carrie figures out that the plane was the real reason Pryce was sent to Antarctica. Suddenly, the tunnel collapses, snow rushing into the plane, trapping the group. When all seems doomed, Pryce remembers that Russian plans from the 1950's had exploding roof hatches and is able to explode the hatch with the battery from Carrie's GPS. The three climb out and share a bottle of vodka in the snow cat as they plan their next move.
The group returns to the facility where Carrie informs Sam that a serial killer is on the loose. Carrie then goes to see Doc about her fingers. Doc examines Carrie's fingers, which are black with frostbite. Carrie has no feeling in her fingers and Doc tells her that they will have to be amputated. Doc and Carrie talk about happier times while Doc preps Carrie for the amputation. We hear the clip as Carrie's pinky finger is amputated off screen.
Carrie returns to her office to retrieve her gun and after a visit by Pryce where she reveals her past in Miami she confronted by Rubin. Rubin explains that they had found the plane on the meteorite search and that they had taken the canisters. Rubin explains that someone is trying to kill them. Carrie says she will escort Rubin to the plane that is leaving and will ensure that the killer is caught. As Carrie gets Rubin ready to leave, an outside door opens and the killer appears. The killer bashes Rubin onto the ice, swinging his ax then snaps his neck. Carrie knocks the killer out with a shovel.
Carrie and Pryce reveal Russell as the killer. Russell explains that he has the Russian canisters with him. All of the other scientists are boarding the plane as there is only a few minutes until the huge winter storm hits. Carrie and Pryce lock Russell in the brig and discuss the need to find the canisters.
In the confusion of the evacuation, Carrie and Pryce cannot find the canisters. Carrie then discovers that Delfy has been stabbed and Doc attends to him. Carrie and Pryce find out that Russell has escaped and see him escaping and trying to get to his plane on the ice. As the larger plane leaves, Carrie and Pryce chase Russell across the ice. The chase continues when the whiteout hits. For several minutes the three chase each other on the ice, using the system of security ropes. Just when it looks as if Russell is about to kill Carrie, Pryce appears and cuts Russell's rope, sending him flying into the cold killing him. Carrie and Russell return to the base, open Russell's bag and find the missing canisters. When they open the canisters they find only jelly beans.
Carrie decides that the original contents of the canisters were hidden in the cargo on the plane. Carrie contacts Sam who is searching the plane for any missing cargo. He says he will send Carrie a manifest. Carrie retrieves the cargo manifest from the fax machine and notices that three packages from the science center were not loaded on the plane. Carrie goes to the science center and determines that the missing packages are the bodies of Rubin, Mooney, and McGuire. She opens each body bag, but finds nothing. While searching through McGuire's body bag, she notices the distinctive stitch on his leg wound matches the ones on her amputated fingers. She opens McGuire's chest wound, reaches inside and retrieves several bags of large diamonds. As she turns to leave, she sees Doc in the doorway.
Doc admits his role in the diamond smuggling and says that Russell got greedy, leading him to murder the others. He says that he has nothing to go home to and the diamonds would give him a new life. Carrie says she feels betrayed by her friend, and would have to turn him in.
The Doc makes a final drink and remarks to Carrie, "The Aurora Australis is pretty special this time of the year. You haven't really watched it, have you? I'd like to see it one last time. You owe it to yourself to see it sometime, it's a he** of a show." He moves to the exit door, opens it and struggles out into whiteout conditions and disappears. Carrie stands there, seemingly stunned, but allows him to exit to his death. For some time she just stares out the door while the storm blows in and snowflakes melt on her face.
Six months later. Carrie, Pryce, and a recovered Delfy have wintered through at the facility. Pryce and Delfy are bowling in the hall with the canisters and a huge rubber band ball. Carrie chats with them and goes to her office where we see her transmit an email to her director for a new post.
Then we see her starting to go somewhere and and the others ask where she's going. She indicates she needs to take a look around. She puts on her cold weather gear and goes outside. She hasn't gone far before she is struck by the beauty of the Aurora lights in the sky, finally taking the time to look.