This documentary incorporates the footage shot by Sidney Bernstein, head of the Allied Film Section of the Psychological Warfare Division, under wartime conditions, two or three days after the Allied troops liberated Belsen and other Nazi concentration camps. It depicts the unspeakable carnage of thousands of corpses being buried in large pits. The film was made as a record to show the German people what had been allowed in their country under Hitler. It was judged to be too harrowing for viewing at the time and was suppressed by the British government. In updated sequences, Bernstein describes the filming of these wartime atrocities and the assistance he received from Alfred Hitchcock. Survivors of the camps recount their hellish experiences.