The collective crimes against humanity known as the Holocaust have been well-documented since the end of World War II, but lingering questions remain about how much was known about the Nazi mass-extermination schemes outside Germany, and what could have been done to prevent them. Political filmmaker Costa-Gavras confronts this thorny issue in this film, adapted from the stage drama The Representative and based in part on actual events. Kurt Gerstein (Ulrich Tukar) is a German chemist whose work on various government health projects led to him being added to the scientific staff of the Nazi SS. While working on disinfection and water purification programs to stem the tide of typhoid among German troops, Gerstein creates a toxic cleanser called Zyclon B. Gerstein soon learns that the SS has found a different use for Zyclon B -- in gas form, it is being used to exterminate Jews and other political undesirables en masse. Gerstein, a man of strong Christian faith, is horrified by this revelation, and he is determined to tell the world in hope of stopping the genocide; however, in Germany, Sweden, and the United States, Gerstein's story falls on deaf ears. One man who does believe Gerstein is Riccardo Fontana (Mathieu Kassovitz), a Jesuit with ties to the Vatican and close contact with Pope Pius XII (Marcel Iures). Fontana urges the Pope to speak out against the ongoing massacre, but the Pope declines, believing Russia is a greater menace to the Catholic Church than the Nazis. In time, desperate to spread the word of the holocaust, Gerstein and Fontana find themselves joining ranks with Roman Jews being rounded up by Nazi forces in occupied Italy.