A terrified woman (Alex Paxton-Beesley) and a man (Eric Murdoc) run in a corridor. They are running away from something or someone. They reach the end of the corridor and they bang on the door, shouting for somebody else to open up the door.
In a grim future world, when people have to live underground because on our planet a new Ice Age has begun, the scarce survivors try keep civilization while waiting for a better future. Briggs (Laurence Fishburne) is the leader of one of these underground places, called colonies. Colony 7 has its own problems. The lack of food and medicine make something as "mild" nowadays as the flu really dangerous, which can lead to a disaster of epidemic proportions. Briggs tries to keep civilization in Colony 7. He has organized a system of 40-day quarantine, to give people the opportunity to get over the flu. After a flu epidemy has killed twenty people within the colony, he has devised a system in which people who are sick after the quarantine period is given a choice: they may be killed, or they may try to live outside, on their own, and try to survive by their own means. Not everybody agrees with these system, though. Mason (Bill Paxton) kills Hal (Sten Eirik), a man who couldn't get over the flu completely, in fear that he would eventually return to the colony, as there is no way for a single human to survive for long in the frozen prairie which our planet has become.
Sam (Kevin Zegers) has told Mason to let Hal go, as he has chosen to leave. Hal says that it's not a choice, it's survival, and one less person will mean more food for the rest. Sam explains that people from the cities which reached one of the colonies considered themselves lucky to reach one of the colonies. At the beginning, they had to make do with crammed conditions, but then, people's life expectancy started to dwindle, and now, they are not crammed at all. At colony 7, attempts to keep seeds for when the Ice Age finishes have been done. Sam tells Briggs that Mason killed Hal - Briggs doesn't like that.
An SOS from Colony 5 is pulsing two days after the colonizers had said that they were disconecting the radio for some repairs. All the inhabitants of the Colony are called in for a meeting. Briggs tells Mason off, but he makes his disgust clear. Kai (Charlotte Sullivan) is Sam's girlfriend. She keeps seeds locked - she has her laptop connected to an old satellite. When Sam tells her that Hal "has died", she is more accepting. In the meeting, people are on the merge of freezing. Two people are trying to disguise the fact that they are suffering from the flue. Sam says she's already fixed the ventilation system, but for them, it's too late.
In this meeting, Briggs says that he'll go to Colony 5, and that he needs two volunteers to go with him. As usual, Mason disagrees - if they bring more people to their own colony, food would be even more scarce. Sam offers himself to go, as Kai will be the person responsible for the turbines' maintenance. Graydon (Atticus Dean Mitchell) offers to go, even though he doesn't have much experience on being on the ground. When Elena ( Kristin Shepherd) coughs, the meeting is called off sooner, as everybody panics. She and her husband are put in quarantine. Briggs says that Kai will be the leader while he's away.
That night, Sam dreams of himself as a child (Mitchell Nye), lost in a polar storm, dressed in fur, watching his parents' dead bodies. Sam wakes up and goes to wash his face. Kai also wakes up, They kiss each other.
Briggs, Sam and Grayson leave the colony in the freezing cold. Sam looks at the overwhelming frozen desert outside the colony, and reminisces of stories he heard when he was a child. Global warming brought the ice age. One day, it began to snow, and it has never stopped since. Humans tried to change the weather back with some tall structures, - they have to pass the remains of one - but they didn't really work. Later, they have to cross a frozen bridge, full of holes. The river below looks half-iced, but it is not considered safe to cross it on foot. In the middle of the bridge, they find a frozen truck. The dead body of a man lies outside, with a gun by his side; inside lies the dead body of a woman which was shot in the forehead - probably killed by the man outside in desperation when their truck got stuck and they couldn't cross the damaged bridge on it. The three of them also find an emergency helicopter which was used to evacuate people. Inside, they find a caption written on the frozen mist on a window "HELL HAS FROZEN OVER". They use walkie-talkies to communicate with their colony: they are told that the couple is still sick with the flu. Briggs tell them to wait until he comes back. They will sleep inside the helicopter and then move onto Colony 7, which they will reach by midday the following day. Grayson looks at two models in bikinis, Nadia and Crystal - Sam and Briggs can see he's enjoying the experience a lot. Sam says he can't remember when he saw the sun for the last time.
When they finally arrive to Colony 5, they see a blood trail outside. Briggs says that they have come to help, so that they should enter anyway, in spite of Graydon's concerns. They smell of smoke, threw a light to see how deep the chimney goes, and they go down by the hand ladder. Graydon would have rather wait outside, but Sam tells him to come down with them.
Inside, there are pools of blood everywhere. The three men move around quietly. They find a terrified sleeping man who insists in having the door closed. Leland (Julian Richinds) shows them a message they found: a colony has succeeded in making one of the weather towers towers, melting the ice, dispersing the clouds and even bringing in fertile soil. Briggs writes the localization of the spot, which is the only unclear part of the message. The who speaks is sending out a message, as they haven't got seeds to plant on that soil, so they ask for some other colony's collaboration. Colony 7 sent out some people to that place, which lies outside of Briggs' map, but nobody has returned. Briggs wants to take Leland back with them, but he doesn't want to go. He says that there's somebody else in the colony. Some weird noises are heard. Leland pushes the three of them out, and he locks himself in his communications room again.
The three travellers wander around the compound in search of the origin of the pounding. They see a man butchering human remains, and some deformed people - they look like the product of miscegenation - feasting on other human beings. The butcher realises they are there and ties to attack them with their butcher's knife. Briggs and Sam shoot some people while running away. They use a hand bomb to give themselves more time to run. Graydon is attacked by several cannibals. Although Briggs and Sam help him, Graydon dies, and his two friends have to leave his body behind.
The cannibals run after the two survivors. Briggs and Leader of the cannibals (Dru Viergever) look at each other, measuring their own strengths. Briggs blows out the entrance of the place, saying that the inhabitants of Colony 7 are beyond their help. They have to rest in the helicopter in spite of the danger, because temperatures are descending dangerously. They are sad for Graydon.
The cannibals chase them. Briggs and Sam have to hump a huge hole. Briggs uses dynamite to blow up the bridge, delaying them for a while. Briggs has to set fire to the dynamite again. Finally, the dynamite goes off, creating a huge gap in the bridge but killing Briggs at the same time. The leader stares menacingly at Sam, who runs away to his colony.
Sam arrives at Colony 7. Mason kills Elena instead of doing the flu test to her. Kai aims her gun at Mason, but at that moment, Sam arrives. Kai runs to him. Sam faints and Mason uses his shotgun to knock Kai down. When Sam wakes up, he is put in the infirmary and is handcuffed by Mason. Mason nominates himself as the leader, saying that he will reduce food rations by half. Mason doesn't believe Sam when he tells about the cannibals.
A boy steals the keys to the cuffs - a boy which Briggs had kindly reprimanded before. Sam frees Kai. Mason learns that Sam has escaped. Sam and Kai look for the location of the ice-free area though Kai's connection to that old satellite. They find a spot of a 12-km gap of blue cloudless sky. Sam takes some random seeds and throws them into his handbag. Mason won't let him and Kai go - he doesn't believe Sam's words yet. Immediately, they listen to the bumping made by the invading cannibals. Sam tells that it's too late now, and that he'll be the king of an empty castle. Mason orders everybody to go to the meeting hall in order to defend the colony. Mason accuses Sam of showing the cannibals their location. The power goes off, and back on. The cannibals try to attack them from their back. The cannibals are moving through the ventilating system. Sam kills a cannibal who was attacking Mason on his back.
Sam suggests to leave the place, but some of them want to fight. As they are outnumbered by the cannibals, Sam tells everybody to go back to the meeting hall. A few survivors try to leave through the ventilating system, and one of them stays behind to blow everything up. The leader of the cannibals survive. He and Sam fight face to face. The leader looks to be winning - he shows Sam his sharp pointed teeth while the room starts to burn. Sam hits him with an iron bar, beating him repeatedly in a frenzy. Sam is about to leave, but the leader stops him. Sam uses a butcher knife to cut his head in half.
A small group of people succeed in leaving Colony 7. Mason stares at the burning remains. Sam shows them a tin of some produce, and he tells them that they have what they need to survive.
They are leaving in search of the warm place.
---written by KrystelClaire