Germany, 1932: On their honeymoon, William and Dinah Conway cross paths with Winston Churchill and witness a meeting that almost changed history. Back in London, as the threat of war looms, the young couple is pulled into a perilous world of secrecy, taking great risks for the sake of conscience. The arrival of William's mysterious cousin Victoria Gauntlett brings another threat to their happiness. What is her real aim as she works her way into their lives? And what is her pull to Munich, where William and Dinah must return for the sake of young Rosemary, another cousin? Kent, 2001: Lottie Conway has lived with her family's notoriety, knowing that her grandfather, William, was a traitor, and that two women - Victoria and Rosemary - caused a scandal that still fascinates the world. Sent to New York to report on the sale of Victoria Gauntlett's paintings, Lottie starts to learn about her family history. Only one person knows the truth about what happened all those years: her grandmother, Dinah, now increasingly lost to dementia. But is it too late for her to reveal her secrets?