Historian Grace Karskens looks for answers about her father's brother and his links to Nazi Germany; retiree Ming Balintong tries to uncover his father's name, find a photograph of him and learn more about his life.

Paula Morrison uncovers the truth about her Austrian-born father's upbringing and the abuse he suffered; siblings Rod Cordery and Sandra Rowlands look for answers about the identity of their biological father.

On this episode of Every Family Has a Secret, host Noni Hazlehurst meets two women with amazing histories they need to unravel.

Two Melbourne women embark on a journey searching for their true identities. Melbourne academic Dr Sofia Rios Miranda examines whether there is any truth to persistent family rumours that her great grandparents abducted a British baby boy and changed his name, raising him as their own. Was it a kidnapping, or cruel gossip?

Meanwhile, adoptee Dr Penny Mackieson investigates how she was a victim of a baby swap at a Melbourne hospital in 1963. In her twenties Penny re-united with her birth mother and spent the next 20 years bonding with her. But then Penny's world was turned upside-down when a DNA test revealed that she had Greek heritage, challenging everything she believed about her identity. Now Penny is determined to re-unite with her true biological family.

Siblings Jacquie Blatchford and Michael Damnjanovic try to uncover their French-born mother's mysterious past. Investigations reveal links to far-right political movements and also shed light on Michael's biological father.