Inspired by the true story of two sisters who helped Jewish people escape fascist Germany, a powerful, compelling novel of love, courage and sacrifice. Her hands tremble as she tightens her grip on the letter, taking in the familiar script that is scratched into the fading parchment. For more than thirty years, she has carried this testimony - these secrets - with her. It's time her story was told. 1937. As fascism rises across Europe and the threat turns to very real danger for their Jewish friends in Berlin, sisters Josephine and Constance smuggle out possessions to help to finance their friends' new lives as refugees in London - if they make it out. Then, one day, they're asked to rescue something much more precious: a little girl. Her mother, Ilse, has been imprisoned for her journalism and her father, Daniel, knows he must do all he can to protect their child - even if that means letting her go.

1939. When war breaks out, the sisters are tortured by thoughts of those they couldn't save and commit to doing all they can on the Home Front - Jo, at the Ministry of Information, where she becomes part of a network of intelligence workers, and Constance as an air raid warden during the Blitz. Meanwhile in Germany, Ilse is moved to Ravensbrück, where she bands together with other women in the camp to expose the atrocities they face every day. But can Ilse find a way to connect with her daughter?.