Idriss Gabel and Marie Calvas are grandchildren of Rudolf Heß' last chaplain in Berlin-Spandau prison. The fanatical anti-Semite Heß was Adolf Hitler's deputy in National Socialist Germany and co-author of the Nuremberg Race Laws. As a French military chaplain, Charles Gabel was the only person authorised to speak privately with Hess for almost ten years. In this documentary, his grandchildren ask: What kind of relationship did their grandfather have with this Nazi leader? Heß was sentenced to life imprisonment in 1946 as part of the Nuremberg trials. He served the sentence throughout the Cold War period as the sole inmate of the huge Spandau prison. In 1987, he took his own life at the age of 93.