In 1943 the British and Americans plan the opening of a ‘Second Front’ in Northwest Europe. Huge numbers of troops, aircraft and ships begin to assemble in England for the invasion of France. They train relentlessly for what will prove the largest amphibious operation in military history. Meanwhile across the Channel the Germans also gather their strength. Hitler sends one of his best generals, ‘the Desert Fox’ himself Field Marshal Erwin Rommel, to supervise the construction of coastal defences known as ‘the Atlantic Wall’. But the Allies retain one crucial advantage that even Rommel’s genius cannot compensate for – only the Allies know where and when they will strike.