Amen

Kurt Gerstein, an SS officer assigned to the SS Hygiene Institute, works on programs for water purification and vermin destruction. He discovers that his hydrogen cyanide compound Zyklon B, developed to combat typhus, is being repurposed for mass murder in extermination camps. The revelation shocks him to the core.

Seeking to prevent further atrocities, Gerstein attempts to warn Pope Pius XII about gas chambers and gassings. He is appalled by the Vatican's vague and tepid response to his reports. He resolves to press the issue despite the Church's hesitations.

Riccardo Fontana, a young Jesuit priest, partners with Gerstein to publicize the Nazi crimes. They work to bring attention to the atrocities across Europe, hoping to mobilize moral leaders. Their collaboration marks a rare cross-boundary effort to expose the crimes.

Gerstein travels to Rome to speak to the Pope, hoping for decisive action. As he arrives, the German advance tightens its grip on the city, and Rome becomes a center of fear as Italian Jews are rounded up for deportation.

Fontana pleads with the Pope to intervene by appearing at the train station to halt the deportations. The Pope refuses, arguing that stepping into German-ruled territory would harm Christians living under Nazi rule. In defiance, Fontana publicly marks himself with the Star of David and boards the deportation train.

Fontana is interrogated by the camp's top official, known as the Doctor, who is an ally of Gerstein. Despite knowing Fontana is a Catholic priest, the Doctor allows him to stay among the Jews and work in the crematorium.

As the war nears its end, the Doctor orders Fontana to be gassed, turning the priest's presence among the inmates into a final act of witness amid the killings. Fontana's fate becomes a grim testament to the camp's brutality.

Gerstein makes a last-ditch effort to rescue Fontana, but Fontana refuses to abandon the others. The Doctor escorts Gerstein out of the camp while the executions continue, sealing Fontana's fate and leaving Gerstein with decisive evidence of the crimes.

The convoy passes a mass grave nearby where Jews have been murdered and their bodies burned or buried. The Doctor probes Gerstein for contacts who could help him escape Germany, highlighting the dangerous web of complicity and survival.

Gerstein returns home and compiles his evidence documenting Nazi atrocities, delivering it to the Allied forces. Despite the testimony, he is arrested on charges related to his wartime activities, and his fate becomes a matter of contested legality.

After the charges are read, Gerstein is found dead, hanging in his prison cell. His death ends a controversial life spent cataloging the crimes of the regime and seeking accountability.

In the aftermath, the Doctor seeks assistance from a Cardinal in Rome to leave the country, insisting that he is a doctor, not a criminal. The Cardinal agrees to help arrange the Doctor's escape to Argentina, offering a glimmer of asylum amid the collapse of the Nazi empire.