By 2045, humans have built weather machines to control the warming climate due to climate change and global warming. The machines break down when one day it begins to snow and doesn't stop. Whatever humans remain live in underground bunkers to escape the extreme cold. Their challenges are controlling disease and producing sufficient food. Two soldiers, Briggs (Laurence Fishburne) and Mason (Bill Paxton) are the leaders of one such bunker, Colony 7. Briggs, Sam (Kevin Zegers) and Graydon (Atticus Dean Mitchell) travel to nearby Colony 5 after receiving a distress signal. Briggs leaves Sam's lover Kai (Charlotte Sullivan) in charge of the colony while he's gone, much to Mason's chagrin.