December 1942. Two young soldiers leave their post at check-point 83 in Northern Värmland, Sweden, and make their way through the ice cold winter-night towards the border of Nazi-occupied Norway. Sweden stands on the brink of invasion and the soldiers want to see the enemy everybody's talking about. But the adventure ends in disaster and the following day Lieutenant Aron Stenström finds out that his brother Sven is one of the missing soldiers. With the odds against him, he is forced to go on a secret rescue mission behind enemy lines. Deep in the Norwegian forest Aron realizes that a completely different kind of line must be crossed if they're to come out alive.