In 1941, a young Belgian woman organised an escape line, crossing rivers and traversing mountains in order to spirit hundreds of British soldiers back to England. The Comet Line, as it became known, was the greatest escape service of the Second World War.

By that stage of the war, it was clear that the fate of Europe would be decided in the air. It took tens of thousands of pounds and many months to train fliers. Each shot-down airman who returned to Britain was worth more to the Allied war effort than the plane he flew in. Dédée's courageous work was not only heroic at an individual level, but hugely significant on a global scale.

Based on previously unseen archives, including personal letters and intelligence records, the acclaimed New Yorker writer Ed Caesar tells the epic story of one woman's courage, her commitment to keeping the flame alive during the darkest hour of European history and her team's incredible work to realise her vision.