In Germany the Kriegsmarine played no role for many centuries. It was not until Kaiser Wilhelm II built a fleet of his own to protect the German colonies and defend against a British naval blockade. Being hopelessly under the British navy, the Imperial Admiralty preferred the use of submarines to achieve the greatest possible military effect with relatively small means. In the Second World War, too, the German submarines played a central role in the naval war until the Allied oversight and new detection systems hunted the hunters. Of the 40,000 U-boat men of the German war marines, 30,000 did not return home. The film tells the exciting story of the German U-boat arm from the early beginnings to the surrender in May 1945. In addition to the 66-minute feature film, the DVD features 117 minutes interviews with important German U-boat commanders: Erich Topp, Otto Kretschmer , Rolf Thomsen, Gerd Kelbling and Reinhard Hardegen.