September 1939, the Germans are invading Poland, and as Britain declares war a leading national newspaper posts its journalists to the European countries that have yet to fall under Nazi rule. Colin Metcalf (Hugh Williams) is sent to Norway but his ship comes under attack from a German U Boat and he soon learns of the Nazi plot to invade. Having escaped from the Nazis, Metcalf returns to his newspaper in England and writes a series of articles on his Norwegian experiences. These soon attract the attention of Naval Intelligence in London where he is recruited for a dangerous mission. Metcalf must return to Norway, link up with the resistance, and assist with the destruction of the German U Boat base that is responsible for the sinking of the North Atlantic convoys. The outcome of his perilous assignment could change the course of the Battle of the Atlantic!