In 1945, during the liberation of the Nazi camps, allied forces discover an odious image: corpses covered the ground, the smoke was rising over the unburned bodies, and barracks were filled with the dead. Retreating, Germans hastened to destroy the traces of their crimes, and allies were able to capture the most shocking images of the twentieth century on film. Using the archives of the British, American and Soviet armies, the filmmaker Sidney Bernstein makes a documentary, showing what had happened inside the Nazi camps. Alfred Hitchcock also helped him with the movie. It is said that he was so shocked with the images that did not show up at the studio for a week. The film also shows the liberation of Dachau, Buchenwald and other concentration camps.