When World War II ended in Europe, Grand Admiral Donetz radioed all of the German U-Boats at sea to cease hostilities and surrender the boats at the nearest port controlled by the Allies. Then most of the boats were either scuttled or surrendered. One well-known exception was U-977 that had left the coast of Norway on a combat patrol two days prior to the order to surrender. Its skipper decided that he would rather be interned in Argentina rather than surrender and be a POW. U-977 was equipped with the newly installed snorkel so it was able to stay submerged using its diesel engine and bringing fresh air in to the crew. It stayed submerged for 66 days until it came up off the African coast near the Cape Verde Islands to allow the crew to be able to leave the boat for a short rest, then proceeded to Argentina, where the boat and crew were interned. This created the idea for a fictional submarine, U-724, that makes a similar attempt but for a very different reason. That leads to this adventure 60 years later by a small U.S. Navy crew working for the Office of Naval Intelligence.