On July 20th, 1944 Oberst Graf Schenk von Stauffenberg attempted to kill Hitler in his headquarter in Poland with a bomb. The film recontructs the events chronologically and meticously until Stauffenberg`s execution.
In the same week that "It Happened on July 20th" went to the screens, another film on the same subject "The Plot to Assassinate Hitler" by Dr. Falk Harnack, a former member of the Stauffenberg circle, was released. Comparing the two films most critics favoured Harnack`s movie.
Oberst (Lt. Com.) Gernsdorf, also a member of Stauffenberg`s resistance group, served as a military adviser.