1942. Hannah Martel has narrowly escaped Nazi Germany after her fiancé was killed in a pogrom. When her ship bound for America is turned away at port, she has nowhere to go but to her cousin Lily, who lives with her family in Brussels. Fearful for her life, Hannah is desperate to get out of occupied Europe. But with no safe way to leave, she must return to the dangerous underground work she thought she had left behind.

One morning while passing through Grand Central Terminal on her way to work, Grace Healey finds an abandoned suitcase tucked beneath a bench. Unable to resist her own curiosity, Grace opens the suitcase, where she discovers a dozen photographs - each of a different woman. In a moment of impulse, Grace takes the photographs and quickly leaves the station. Grace soon learns that the suitcase belonged to a woman named Eleanor Trigg, leader of a network of female secret agents who were deployed out of London during the war.

Brought to the peace conference by her father, a German diplomat, Margot Rosenthal initially resents being trapped in the congested French capital, where she is still looked upon as the enemy. But as she contemplates returning to Berlin and a life with Stefan, the wounded fiancé she hardly knows anymore, she decides that being in Paris is not so bad after all. Bored and torn between duty and the desire to be free, Margot strikes up unlikely alliances: with Krysia, an accomplished musician with radical acquaintances and a secret to protect; and with Georg, the handsome, damaged naval officer who gives Margot a job.

After being stolen from her wealthy German parents and raised in the unforgiving wilderness of eastern Europe, a young woman finds herself alone in 1941 after her kidnapper dies. Her solitary existence is interrupted, however, when she happens upon a group of Jews fleeing the Nazi terror. Stunned to learn what’s happening in the outside world, she vows to teach the group all she can about surviving in the forest—and in turn, they teach her some surprising lessons about opening her heart after years of isolation.

From the author of The Lost Girls of Paris comes a riveting tale of courage and unlikely friendship during World War II - now a New York Times best seller.