Nine celebrities trace their family trees to explore the lives of their ancestors and uncover major themes in British social history. Award-winning actor and Broadway star Alan Cumming made his name playing roles in films such as Goldeneye and X-Men. However his childhood was spent far from the glamour of Manhattan where he now lives. Growing up in the small town of Aberfeldy, Scotland, Alan knew very little about his family history. With his parents now both in their seventies, he feels it's time to see if he can clear up one big question lingering in the family's past. The mystery relates to Alan's maternal grandfather, Thomas Darling. A career soldier who spent most of his life away from home serving in the army, he died, aged just 35, in mysterious circumstances in Malaysia. Alan begins by visiting his mother Mary in Dundee, to see what she can tell him about her father. Mary has few memories of him, but she has some documents relating to his military career and a medal he won in the Second World War. She hopes these clues will get Alan started in his search. Alan travels to France where he finds out about his grandfather's extraordinary bravery during the evacuation of Dunkirk - he's thrilled by his grandfather's medal-winning exploits. Eventually Alan's journey takes him to Malaysia where he discovers the shocking story of how his grandfather really died and makes one last moving discovery about the lasting impact his grandfather made on the village where he was stationed in the months leading up to his death.