Germany in 1941. War in Europe for two years. The Nazis at the height of their power. Since the beginning of the war, there has been a frontline in the west where the traces of horrible fights disappear on the spot:The Battle of the Atlantic. England, traditionally the leading naval power worldwide was to be cut off from all supplies by a blockade while the balance of power is not in favor of the German Kriegsmarine. Their commander-in-chief complains that "the war was five years early." That a victory seems achievable at the beginning is the result of a weapon that was only known in Germany at the height of perfection and drill: submarines.