As Gestapo chief in Paris, Kurt Lischka ordered the largest mass arrest in French history in 1942 and was responsible for the deaths of 33,000 Jews. After the war he settled quietly in Cologne, shielded by a legal loophole that protected Nazis holding German citizenship from prosecution. This film follows Serge and Beate Klarsfeld, the Nazi hunters who tracked him down decades later and confronted him in the street, filming him running from them in an attempt to shame West Germany into changing its statute of limitations laws. Interviews and archival footage trace the couple's long campaign, including Beate's earlier public slap of a West German chancellor as a protest against former Nazis in government, and the political fallout their pursuit of Lischka triggered in Bonn and Paris. The film lays out how a private husband-and-wife investigation turned into a legal and diplomatic fight that eventually forced Germany to close the loophole protecting men like Lischka from facing trial.