From 1943, Nazi Germany started working on terror weapons, the V-1 flying bomb and V-2 rocket while British Intelligence learns about a new secret weapon. Technical problems with the V-1 lead the Germans to create Fieseler Fi 103R Reichenberg to ascertain the flight problems of the rocket but all the test pilots are killed flying it. Aviator Hanna Reitsch (Barbara Rütting) successfully flies and lands the V-1 prototype, discovering the problem (mechanical shifting of the rocket's weight and change of speed) and how to solve it, which leads to the mass production of the V-1.