The inspiring, heart-thumping true story of the couple who brought some of the Holocaust’s most notorious Nazis to justice. Almost sixty years later, they’re still at it, and their work is more relevant than ever.

It all began on a Paris subway platform in 1960. Beate Künzel, a German au pair, was waiting for the Line 10 train when a bespectacled young man struck up a conversation. They rode into the heart of the city, side-by-side, and by the time he got off at his stop, the man — Serge Klarsfeld — had tucked Künzel’s phone number into his pocket. Before long, they were married, and their partnership proved to be a love affair that not only thrives to this day but literally changed the course of history in post-World War II Europe and beyond.  

Their marriage was an unlikely one: They had been on opposite sides of a war whose fallout was still rippling through Europe. Serge, a Romanian-born French Jew, had lost his father to the death camps at Auschwitz. Beate’s father had voted for Adolf Hitler and fought for the Germans. Their union — and the unique kind of family business they came to operate — would be the stuff of a Hollywood spy thriller, turning this seemingly unremarkable husband and wife into surprise heroes for justice.

The Klarsfelds, motivated by outrage that high-ranking officers from the Third Reich were living freely in France and elsewhere, dedicated themselves to a singular goal: finding Nazi war criminals and bringing them to trial. The list of men they tracked down reads like a who’s who of Hitler henchmen and French collaborators: Klaus Barbie, Kurt Lischka, Herbert Hagen, Alois Brunner, Maurice Papon, and René Bousquet. Together, they were responsible for hundreds of thousands of deaths. The Klarsfelds became notorious throughout Europe, a vigilante Bonnie and Clyde who staged public protests and even attempted kidnapping one of their targets in their effort to pressure local governments to prosecute these criminals. By 1972, the Klarsfelds had located Barbie — a.k.a. the Butcher of Lyon — who was hiding in Bolivia. The following year, they tracked down Lischka, one of the highest-ranking Nazis in occupied France, responsible for thousands of deaths in the concentration camps. Despite death threats, a car bombing, imprisonment, and more, the Klarsfelds persisted, eventually compiling mountains of evidence that were instrumental in bringing Barbie and others to justice.

Part love story, part adventure yarn, the Klarsfelds’ long life together is a reminder that all of us have the capacity to change the world for the better. Their work has been an act of remembering not just the barbaric behavior of criminals who tried to hide from the history books but the courage of the many average people whose stories of bravery and sacrifice might never have been recorded at all. More important, they’re still at it. Now well into their eighties, they continue to uncover and record atrocities and to share the stories of the many who died at the hands of the Nazis. Sadly, perhaps, their relevance hasn’t diminished. In a time when far right-wing politics are becoming increasingly mainstream and the threat of anti-Semitism has once again reared its ugly head in Europe, the United States, and elsewhere, the Klarsfelds’ passion and devotion remain an important bulwark against a rising tide of hate and a testament to the power of moral courage.