September, 1944. Fresh from liberty on the Island of Hawaii, Horatio Culpepper, Captain of the USS Seaviper, receives an order from Vice-Admiral Stallerman, along with Top Secret information from President Roosevelt, to rescue a downed American airplane near Sumatra. The downed pilot, an American Navy Airman, is rescued with two escaped prisoners-of-war from a nearby island. But the Japanese and Germans are also discovered to be on this island together and USS Seaviper's landing party is forced to seperate. They discover that the Germans have converted a mine laying U-234 into a long range submarine and that they have transported a deadly cargo across the Pacific to deliver it to the Japanese. Why is the cargo so important?