A small child lies in bed asleep. With head on soft pillow and teddy in hand, she slowly wakes up to a horrible day. ""I dreamed that I''d had a nightmare"." Looking around at her familiar surroundings she remembers that "the sad dream was a reality". Yesterday her father was convicted and hanged "in the name of thousands of victims of concentration camps and mass graves". Life will never be the same again.

How could this be? Hanns Ludin was an honest, upstanding, noble man, a "bon vivant" and father to six children. He was also an idealist. Joining the army young he was soon attracted to Hitler; "his goals are absolutely great and what he wants is pure"". Later on, as a charismatic public speaker, he called on fellow officers to "courageously endure until Germany is free," believing that in so doing the "happiness of children and wives would be secured for generations". Instead, he stands in the dock repeating " "I am not guilty, I am not guilty"".

In an interview Malte recorded with his mother in 1975, she recalled a chilling conversation she had had with the Swiss ambassador''s wife on a Slovakian street. The lady had hidden a Jewish child in the embassy to save it from Auschwitz. ""What's' Auschwitz?"" asked Malte''s mother. ""'You know perfectly well.'" I said "'No, please tell me what that is.'" '"It''s a place where the Jews are gassed".'" Asking a Berlin official what was really going on, she was told it was a munitions factory. ""My husband and I believed him.""

Malte decides to confront the past head on, and meets Jewish Tuvia Rűbner , who lost his family to the holocaust. ""I was reticent to tell this man whose son I am"." In conversation with Malte, Tuvia suddenly realises that his father "is the one to whom his family fell victim". There is an awkward silence as both men face the awful way in which their family histories are linked.

Searching through the archives we discover the extent of Hanns Ludin''s involvement. Not only did he know about the holocaust, he participated in it. As ambassador to Slovakia he argued "again and again the political necessity for a total solution"; he "did not have a diplomatic assignment". Despite being sent reports that "masses of Jews were shot down, including women and children", he did nothing. ""Arrested so far 18,937, Special treatment 2,257, Transferred to German camps Jews 8,975,"" - signed - Ludin.

The truth regarding Ludin''s exact role, and how much he knew, has haunted his family. His favourite, Erika, drank to get rid of "her incredible anger". His eldest son fled to South Africa. Those siblings that remain in Germany are in "constant struggle" with one another and themselves over their father''s legacy. What Malte has discovered, has only confirmed their worst fears. Sister Babel still "doesn''t regard their father as guilty," and none of Malte''s other siblings have fully managed to face the truth.