March 1941. Captain Martin Stone is leading a finely-trained platoon of American soldiers on a mission to destroy an enemy bunker, joining forces with an elite platoon of Finnish soldiers led by Captain Niemi and Lieutenant Laasko. Underestimating their enemy’s strength, they are quickly beaten back into the forest. As they try to regroup, they're suddenly attacked by the same soldiers they had just killed a few minutes earlier. Forced to flee deeper into Russian territory, they discover one of war’s most terrifying secrets and realize that they have woken up an enemy far deadlier than ever before imagined.