Denise Grollmus grew up in the US, and was especially close to her grandmother, a Polish Catholic from Warsaw. Or at least, that's who she said she was. On her 28th birthday, Denise discovered that her grandmother had been keeping a secret – that she was, in fact, a Jew who had changed her identity during the war and then continued to keep her Jewishness hidden for almost 70 years. That discovery instantly made Denise Jewish, too.
Denise has spent the last year living in Poland, on a quest to understand what exactly it means to be Jewish in a country regarded by many as a byword for deeply rooted antisemitism and still feared by many Jews as little more than an enormous graveyard.
Treated as an oddity in the US, Denise discovers that her family background is the quintessential Jewish experience in Poland. There, countless Poles are discovering their own Jewish roots, reconnecting with the Jewish life their grandparents or great-grandparents had abandoned or kept secret.
We follow Denise as she explores this improbable Jewish revival in the unlikeliest places. She meets Jonathan Ornstein, a fast-talking New Yorker now directing the vibrant Jewish Community Centre in Krakow. He tells her it's time people changed their expectations of Poland, and realised that it's not only home to the story of Auschwitz and persecution, but also a place where Jewish life can prosper again.
She meets film-makers Katka Reszke and Slawomir Grünberg, who explain how they stumbled over their Jewish roots.
The chief rabbi of Poland, Michael Schudrich, tells Denise why Jewish life was all but erased from the country after the war, long after the Nazis were gone. Just a few thousand Polish Jews survived the Holocaust and chose to stay there. Yet they found that all talk of Jewish suffering during the Holocaust and of Poland's rich Jewish history before the war was silenced under communism. Why?
And what of Poland's non-Jews? What do they make of this new uncovering of their country's buried past? Denise asks Janusz Makuch, the non-Jewish director of the Jewish Culture festival in Krakow, now in its 25th year. Janusz tells her of his own deep need to find out more about the history of his own country – to explore a history that includes a thousand year era when Poland was the epicentre of the Jewish diaspora. And that exploration, explains Barbara Kirshenblatt-Gimblett from the newly opened Museum of the History of Polish Jews, will help Poles discover more about their own identity.
But Denise finds that this Jewish revival and surging interest in all things Jewish can never quite escape the shadow of Poland's darker history. She heads out to a park in Warsaw's Praga district to meet the photographer Lucasz Baksik, who has unearthed the shocking fate of Jewish gravestones, not only during the Nazi period but long afterwards.
So, as Denise's year comes to an end and she gets ready to return to the US, is she any closer to understanding the truth her grandmother kept from her?
• Music by Iain Chambers
• This special edition of Sounds Jewish has been sponsored by the Jewish Community Centre for London and by World Jewish Relief