WARTIME FRANCE, 1944 Trust absolutely no one. This is the only advice newly recruited SOE agent Elisabeth Shepherd is given when faced with the impossible. Her mission: to enter Nazi-occupied France and monitor the Germans' deadly long-range missiles. GUILDFORD, 2018 Betty is celebrating her 100th birthday when she receives an invite from the Century Society to reminisce on the past. She remains mysteriously tight-lipped about her past, however. And then her carer, Tali, discovers a box full of maps, letters and a gun ...