Amen.

During World War II, Kurt Gerstein, a Waffen-SS officer at the SS Hygiene Institute, creates processes to purify water and eliminate vermin. His work is initially aimed at combating diseases like typhus, which is prevalent in the war-torn environment of Europe.

Gerstein's world shatters when he learns that his chemical formula, Zyklon B, is being used in horrific extermination camps to kill Jews and other 'undesirables'. This revelation brings him to a moral crossroads, forcing him to confront the reality of his contributions to genocide.

Determined to alleviate the suffering of the Jews, Gerstein decides to inform Pope Pius XII about the ongoing gassings. He hopes that the Pope can leverage his influence to stop the atrocities, yet Gerstein is met with a disheartening response from the Catholic Church.

Gerstein encounters Riccardo Fontana, a compassionate Jesuit priest who empathizes with the plight of the Jews. Together, they work tirelessly to raise awareness within the Church, advocating for urgent action against Hitler's regime.

Despite Fontana's impassioned pleas to the Vatican for a stronger condemnation of Nazism, their responses remain muted and inadequate. The lack of decisive action fosters despair among those like Fontana who are desperate to make a difference.

Gerstein travels to Rome in hope of gaining an audience with Pope Pius XII. However, he finds himself barred from entry, his message thwarted, intensifying his frustration as the situation for Jews grows increasingly dire.

As German forces tighten their grip on Rome, they commence raids to round up Italian Jews for deportation to death camps. This escalates the urgency for Gerstein and Fontana to act, pushing them to seek refuge for the persecuted.

In a symbolic act of solidarity, Fontana wears the Jewish Star-of-David badge and voluntarily boards a train meant for deported Jews. His choice reflects extreme bravery and a commitment to stand with the suffering, even at great personal risk.

Upon arrival at the camp, Fontana faces interrogation by a terrifying figure known as 'the Doctor'. Despite recognizing Fontana's background, the Doctor permits him to stay with the Jewish detainees, compelling him into harrowing labor at the crematorium.

Gerstein learns of Fontana's situation and rushes to rescue him from the impending carnage. Yet, Fontana refuses to abandon his fellow prisoners, illustrating his loyalty and the shared humanity among them as they face their doom.

As Gerstein is escorted away, he witnesses the grim reality of Nazi atrocities: German soldiers exhuming and burning bodies from mass graves. This harrowing sight deepens his resolve to expose the Nazis' barbarity to the world.

Gerstein returns home determined to compile undeniable evidence of the Nazi's genocide. He meticulously documents his findings, believing this information is crucial for the Allies to mobilize against the horrors he has witnessed.

Despite presenting his evidence to the Allies, Gerstein is arrested instead of being celebrated as a whistleblower. The treachery of the Nazi regime leads to his downfall, reflecting the dark reality of resistance in such a repressive regime.

After being charged with crimes, Kurt Gerstein is found hanging in his cell, culminating the tragic irony of his fate. His efforts to expose the brutalities of the Holocaust end in personal tragedy, highlighting the dire consequences of standing up against tyranny.

Meanwhile, the Doctor, who orchestrated much of the horror, seeks a way out of the impending collapse of Nazi Germany. He converses with a Cardinal in Rome, exploiting his medical status to secure an escape to Argentina, emphasizing the moral decay within the ranks of those responsible for the genocide.