 On December 13th 1939, the first great naval battle of World War II took place off the coast of Uruguay. Known as the  Battle of the River Plate , it set as rivals two great naval officers in a deadly psychological duel. The pocket battleship Graf Spee, the pride of the German fleet, was commanded by Captain Hans Langsdorff, a decorated hero from World War I. Opposing him was Commodore Henry Harwood, an exceptional naval tactician in charge of three smaller, lesser British cruisers; the Ajax, the Exeter and the Achilles. The documentary tells the full story of this sea battle through interviews of the families and crews of the two commanders, bringing a new understanding of the men behind the first major British naval victory of World War II.