Barrow, the northern-most town in Alaska a little bit north of the Arctic circle, is preparing for the annual 30 days
of darkness around winter solstice. As the people who do not want to suffer the extended period of continuous night and extreme cold are getting ready to leave for the south, a lone Stranger (Ben Foster) walks ashore from a large ship caught in thick ice. He makes his way toward Barrow, where he sets about sabotaging the town. First he steals and burns all cell phones, then he slaughters all of the sled-dogs and destroys the only helicopter.
The town´s
sheriff, Eben Oleson (Josh Hartnett) investigates these crimes together with his deputy, Billy Kitka (Manu Bennett). While out and about he learns, that his estranged wife, Stella (Melissa George), who moved out of town a while ago, will have to stay in Barrow due to a car accident en route to the airport. They try to stay out of each other´s way, but when Eben confronts The Stranger in the local diner, she helps arresting him.
From his jail cell, The Stranger tells Eben, Melissa, Eben´s teenage brother and their grandmother that death is coming for them. During his speech, vampires attack the local telecommunications center and power plant, leaving the town cut off from the rest of the world and in the dark. Eben drives to the telecom center and finds the operator´s frozen head on a pike.
The vampires, lead by Marlow (Danny Huston) begin their attack on the town. Marlow directs them in an ancient guttural voice, while the others only shriek. In a matter of hours the kill most of the inhabitants, including Eben´s grandmother. The survivors gather at the diner. After a lengthy discussion they decide to seek refuge in the hidden attic of a nearby house. Meanwhile, Marlow finds The Stranger in his jail cell and kills him quickly as a reward for his work on the vampires´behalf. He then orders his minions not to turn anyone into a vampire; the modus poerandi is to kill everybody and disappear in order to preserve modern man´s opinion that vampires are a myth from the past.
For the next seven days Eben, Melissa and the others stay in the attic. Only a senile old man vanishes, his son gets killed while searching for him. Eben ventures outside to try to help a young female survivor and learns that it is possible to kill these vampires by beheading them. During a blizzard the survivors make their way to the general store, where they are attacked by a little girl vampire. One man gets bitten. The whiteout ends therefore making it impossible to return to the attic. Eben instructs everyone to run to the station house while he tries to divert the vampires by runnig to his grandmother´s house who owns an ultraviolet lamp which she used for growing marijuana. He gets to the house, turns on the generator and burns a female vampire with the light. She is hurt so badly that Marlow has to kill her. In the turmoil eben makes a run for it, but the vampires are in close pursuit. Beau Brower (Mark Boone Junior), the local snowplow driver, comes to his rescue, killing a number of vampires with his plow before crashing into the town´s hotel. There he ignites a box of dynamite, hoping to incinerate the vampires. Alas, to no avail. Eben makes it to the station house, where the man who had been bitten turns into a vampire and asks the sheriff to behead him. He complies.
Two weeks go by. Eben and Melissa see someone signalling across the street. It is deputy Billy Kitka. Eben and Melissa make their way to his house. There he find the distraught man who tells them that he killed his wife and daughters as soon as the vampires attacked and then tried to commit suicide - but the gun jammed. They walk him to the station house where they find out that the others have made it to the power station that controls the oil pipeline, the only building in town that still has power. While the trio is sneaking towards the power plant, Melissa spots a young girl who is being stalked by vampire and sets about saving her. Eben and Billy try to distract the vampire and get separated. Both make it to the power plant, but Billy is followed by a vampire.
Eben is happy to find the rest of the survivors still alive. Inside the building the vampire attacks and bites Billy before getting into a struggle with Eben. Billy jumps to his friend´s defense and offs the vampire by pushing him into the plant´s pump thereby tearing of his right hand. Eben then kills Billy so he won´t turn into a vampire.
A few hours before sunrise the vampires decide to burn down the whole town to cover their tracks. Just then, Melissa radios in that she is stuck under an abandoned truck with the little girl, the flames are rapidly aproaching. Realising that he cannot beat the vampires as a human, Eben in a last desperate injects himself with Billy´s infected blood to become a vampire himself. He kills Marlow in a furious fight. Without their leader, the other vampires disappear.
Eben turns to ashes in his wife´s arms as the sun rises.