How the British and American Naval forces defeated the German U-boats and kept the lifeline to Britain open during World War 2.

The convoy system -- Opening skirmishes -- 'The happy time' of the U-boats -- The opposing forces gather -- The escorts strike back -- The battle spreads westwards -- A notable defeat of the wolf-packs -- Havoc on the American coasts -- The battle swings to mid-Atlantic -- The climax -- Victory