Kurt Gerstein (Ulrich Tukur) is the German chemist who creates Zyclon-B and is horrified to discover that the Nazi S.S. is using his invention to exterminate Jews and "political undesirables." A man of strong Christian faith, he is determined to tell the world in the hopes of stopping this genocide. He is helped in his quest by Riccardo Fontana (Mathieu Kassovitz), a Jesuit with links to the Vatican and close ties to Pope Pius XII.
The inventor of a sterilising substance to purify water for German troops during WW II is compromised when his chemical expertise is employed to produce Zyclon B for the mass extermination of Jews. He is both a member of The Confessing Church and the notorious SS which is an insuperable challenge to his conscience. The film shows Lt Kurt Gersten desperate to broadcast his horrific discovery of the Death Camps to the outside world, at first through a Dutch reporter and later through the Catholic Church who persistently wish not to be involved. Try as he does to forestall and obstruct the programme of extermination, he is still an active agent of what he most deplores. One can imagine that however concerned and distraught Gersten is at the heart of this genocidal machine, the Allies will eventually merely view his defence of his involvement with understandable suspicion.
So my reservation of the film is that in the effort of exonerating Lt Gersten, the dialogue is quite tendentious and the portrayal of other characters are a little unnatural and overly characatured, and on the way to being parodied. Otherwise it is well set with no scenes at all of horror, the long shots of rows of huts and smoking chimneys being enough. The scenes set at the Vatican are quite splendid.