In a rare television appearance, best-selling Harry Potter author JK Rowling sets out to investigate her French roots. Jo has always been intrigued by her late mother's French ancestry, but knows very little about it. Beginning her journey in Edinburgh, Jo's search takes her from The Savoy in London, to once-bloody battlefields and the back streets of urban Paris.

Jo is especially keen to find out more about her great grandfather, Louis Volant. She knows that he was awarded one of France's most prestigious medals, the Legion d'honneur, for his actions during World War One. Jo wants to find out exactly what he did to win the honour. The trail leads to a surprising and shocking discovery.

Pushing back further into her family tree, Jo discovers an ancestor who triumphed against the odds, despite her inauspicious beginnings, and discovers how a war almost transformed her family's identity forever.