"Zero over Berlin," translated from Joh Sasaki's 1988 novel, is based on the premise that the German Luftwaffe, frustrated by its fighters' lack of success against RAF Spitfires in the Battle of Britain, thought it might have better luck manufacturing the Mitsubishi A6M Type 0 Carrier Fighter -- more familiarly known as the Zero -- under license. (The Zero's name comes from the final digit of the year it was produced, 2600 by the old Japanese calendar, or 1940).
So it is agreed that a pair of new prototypes of the plane are to be flown to Berlin for evaluation by the Germans, and two disaffected pilots from the Imperial Navy, Lt. Keiichi Ando and Flight Sgt. Kyohei Inui, are assigned the mission of getting the planes to Berlin.
Despite the plane's long cruising range, in 1940, this journey would not have been easy. Japan's adversarial relations with the Soviet Union precluded a flight over that country. And after Japan's having signed the Tripartite Alliance with Germany and Italy, its military planes would not have been welcome in airspace controlled by the Royal Air Force.