Wartime England: June, 1940. Edward VIII still reigns and mourns the suspicious death of his mistress, Wallis Simpson six years earlier. France has fallen, leaving the bulk of the British Expeditionary Force trapped on the beaches by Rommel's advancing panzers as 300,000 men are taken prisoner. Left with almost no troops, guns or tanks, Britain stands alone against a new, more-powerful German Wehrmacht armed with assault rifles, main battle tanks, superbattleships and aircraft carriers, fast and deadly new U-boats and a pair of 'superguns' firing seven tonne shells across the English Channel. Squadron Leader Alec Trumbull commands a rag-tag collection of broken veterans and inexperienced new-recruits flying a motley collection of worn out aircraft as they take to the skies against the seemingly endless streams of German aircraft. Trumbull's aircraft is damaged in the heat of battle and he is forced out of combat, turning for home in search of safety. Pursued by enemy fighters he can't outrun, he is shot down and forced to crash land on an empty beach, only to be saved at the last moment by a strange and amazing jet aircraft that can land and take off vertically and is piloted by an Australian officer named Max Thorne. Trumbull is taken north to a newly-built installation at the Home Fleet Anchorage of Scapa Flow where he is introduced to the Hindsight Unit - a top-secret task force of men and women who have returned to 1940 from the early 21st Century to combat a group of Neo-Nazis calling themselves the 'New Eagles': an organisation which has also returned from the future to change history and ensure Nazi Germany wins the Second World War. As each side works feverishly against the other to accelerate technology and events begin to spiral out of control, Trumbull finds himself drawn into Hindsight's desperate struggle to prevent a seemingly inevitable invasion of Great Britain and the search to find some way of defeating the New Eagles and returning history to its true course.