The film begins with the recording of a documentary as Doctor David Kruipen, a research scientist in the Canadian Arctic. As the scene progresses it jumps back to some time before where Kruipen, his assistant Jane and two other researchers tranquilize a polar bear before discovering the remains of a mammoth. They take the bear back to their research station where David calls his daughter Evelyn and pleads her to come up. Their relationship has become strained as the recent death of her mother was complicated with the fact that David could not make it to the funeral. She tentatively agrees to come up when he offers to give her all the money left to her by her mother. After getting off the line with her, David and Jane are told that the bear has died and they go to investigate. Meanwhile a group of students, Ling, Freddie and Adam are selected to attend Kruipen's research.
Days later, the research team is feeling the effects of a strange illness, and Kruipen instructs helicopter pilot Bart to not bring his daughter to the station. However Evelyn's insistence forces him to go against David's orders and take her along with the students to the station. They arrive, but no one is there. Evelyn calls out and reaches Jane who learns that despite warning them away as David had said, he did not tell them not to come. In reaction, Jane shoots and apparently kills Kruipen and another researcher and makes her escape. Meanwhile the students discover the bear dead in the research station, and Bart is bitten while touching it. Adam blames it on fleas. Freddie and Ling make up, and Freddie spots a strange bug disappearing where they are sleeping, he admits to having a phobia of them, and goes to sleep in another room. Evelyn is woken in the middle of the night by an ATV approaching the station, when she goes out to investigate, she discovers Jane in the helicopter and they take her in. As the group discovers, Jane destroyed the flight panel, eliminating their chances of getting out quickly. Ling wakes up with many bug bites covering her face and torso, and Jane asphyxiates on her own vomit, dying in Evelyn's arms. Realizing she's sick, Freddie calls for a helicopter rescue for Ling.
Taking the ATV and backtracking, Evelyn and Adam discover the research station, and discover bug eggs in the brain of the mammoth as well as dead bodies. Assuming her father has met the same fate, Evelyn and Adam deduce that something had to make the group sick. They make their way back to investigate Jane's body and decide to quarantine her room. Evelyn decides to cancel the helicopter and quarantine themselves until a better prepared team can come rescue them. Freddie freaks out and destroys the radio in a desperate plea to save Ling, and his own life as he had discovered earlier he too was infected. Bart's arm is getting worse as the bite on his arm has started to display symptoms of the infection. Adam and Evelyn cut off his arm at the elbow and decide they need to destroy the facility and wait it out in the helicopter. Ling is attacked by several bugs who had made their way through the ventilation systems, and Bart discovers that the amputation did nothing as his upper arm now shows signs of infection. He opts to stay behind with Lin and overdose themselves on morphine and fall asleep as the bugs swarm over them.
Freddie goes running out, refusing to be checked for infection before destroying the building and then turns on the other two. As he is about to shoot Evelyn, he is shot from behind by Kruipen who insists they destroy the research station. Evelyn finds one of the recorded tapes he had made earlier and discovers that he, Kruipen, intentionally infected himself, readying to set the bugs loose among humanity to teach them a lesson in global warming's effects. Against his methods, Evelyn and Adam are locked in by Kruipen as the rescue helicopter comes in to pick him up. The kids escape and Adam latches onto the skid, subsequently falling to the ground. Evelyn takes a rifle as the helicopter starts flying away and begins shooting at it, killing the copilot and causing it to crash into the building that they had previously covered in gas. Her father and both pilots go up in the explosion. She runs over to find Adam dying, as he had said to her earlier, he wanted to be there when the ball to global warming started rolling. He dies in her arms, and the next day a rescue team comes and finds the destruction and Evelyn.
Sometime later, amidst early morning radio hosts talking about Evelyn's reports, a hunter calls his dog to leave a dead bird he had been eating. Before the dog runs to the master, one can see an ulcer on his foot, similar to these of Bart and Ling. It means that the dog had already been infected with the ominous insects. A minute later, the bugs begin to emerge from the bird's body. The final shot is the truck heading to a large city