Charles Gabel, the grandfather of filmmaker Idriss Gabel, was the chaplain of Rudolf Hess, a high-ranking Nazi official, close friend, and right-hand man of Adolf Hitler. After being tried at Nuremberg and imprisoned for life in the Spandau Inter-Allied Prison, his grandfather was the only man from 1977 to 1986 who could visit him without the close supervision of the guards. Over the course of their meetings, an extraordinary friendship developed between the man of faith and the Nazi. At the heart of this unexpected relationship, this film invites reflection on the lessons that can be drawn from this sometimes unsettling glimpse into the intimacy of one of the monsters, one of the chimeras of our era.