Imprisoned in a Soviet gulag, young Pole Janusz (Jim Sturgess) soon witnesses the stark brutality of his grim new surroundings. Located in deepest Siberia, where the appalling cold and snow make escape seemingly impossible, Janusz nevertheless meets fellow inmates who are also desperate to flee. Along with stoic American Mr Smith (Ed Harris), murderous Russian criminal Valka (Colin Farrell) and a number of others, Janusz braves the sub-zero temperatures and armed guards in a daring escape bid.
Heading south for Mongolia, it's not long before the group is losing members to the deadly conditions as they try to stay ahead of their pursuers. Starving and terrified that they'll be turned in by any locals they encounter, the group's morale plummets as they argue over which route to take. Meeting orphaned Polish girl Irena (Saoirse Ronan) on their journey, and reluctantly agreeing to let her tag along, the men will soon find that the influence of the Soviet Union has extended far further than they anticipated, making their flight even more treacherous than expected.