S1, E6: Three years after their country was taken from them, an elite force of Norwegian resistance fighters return to their invaded homeland to carry out one of the most daring and significant acts of sabotage in World War II. During the harshest winter on record, they must raid and destroy a hydroelectric plant where the Germans are stockpiling a chemical needed for nuclear weapons research. It could be a suicide mission, but it may be the Allied Forces' only way to prevent Hitler from building the world's first atomic bomb.