Celebrity genealogy series. TV presenter Kate Humble knows little about her family history. What she does know is that her paternal grandfather was a test pilot, and she believes her maternal grandfather ended up in Colditz. On the trail of her grandfather Bill Humble, who was a test pilot during the Second World War, Kate visits the RAF Museum. She is astonished to discover what a legend Bill was in flying circles, and is amazed to see his daredevil flying for herself in archive film held there. Pushing back further on the paternal side of her family tree, Kate finds out that her great, great, great grandfather Joseph Humble was a colliery manager in Northumberland, but mysteriously changed career in his 60s to become a grocer. As Kate delves further into the past, she discovers that Joseph was involved in the worst disaster in the history of English coal mining. Was Joseph in any way responsible for the tragedy? Is that why he left the coal mining industry? Kate also wants to find out more about her maternal grandfather Stanley Carter, and what happened to him as a prisoner of war during the Second World War. At the National Archives, she discovers Stanley's POW liberation report, which reveals that he was at several POW camps but not at Colditz, as she had originally thought. However, she's excited to discover that Stanley was at Stalag Luft III, the scene of an audacious escape attempt immortalised in the Hollywood blockbuster The Great Escape.