In 1939, at the outbreak of WW2, German U-boat captain Günther Prien and his crew receive orders to infiltrate the British Royal Navy base at Scapa Flow and sink British warships.Captain Prien's most prized targets of opportunity would,of course,be any major British battleship or battle cruiser.However, Prien is prepared to attack and sink any target of opportunity,including light cruisers,destroyers,mine-layers or transport ships.German intelligence suspects that some prized British warships are at Scapa Flow,including the famous British battleship HMS Royal Oak.Captain Prien receives his orders directly from Admiral Karl Dönitz,supreme German Naval Commander of the U-boat fleet.Prien and his crew are highly optimistic about their mission.Will their destiny be fulfilled in the Atlantic ?