Simon Wiesenthal, a survivor of the death camps, is hunting down his torturers, from the camp Kapos to Mengele, the mad doctor of Auschwitz. Lawyer and historian Serge Klarsfeld, whose father was deported and murdered, has devoted his life to searching for Nazi leaders still at large. For the first time a film recounts the story of the long pursuit of Nazis in hiding, from 1945 to the present day.