Sixteen-year-old Noa has been cast out in disgrace after becoming pregnant by a Nazi soldier and being forced to give up her baby. She lives above a small rail station, which she cleans in order to earn her keep. When Noa discovers a boxcar containing dozens of Jewish infants bound for a concentration camp, she is reminded of the child that was taken from her. And in a moment that will change the course of her life, she snatches one of the babies and flees into the snowy night.

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.

Rome, 1943. With the fall of Italy's Fascist government and the Nazi regime occupying the streets of Rome, British ballerina Julia Bradbury is stranded and forced to take refuge at a hospital on Tiber Island. But when she learns of a deadly sickness sweeping through the quarantine wards--a fake disease known only as Syndrome K--she is drawn into one of the greatest cons in history. Alongside hospital staff, friars of the adjoining church, and two Allied medics, Julia risks everything to rescue Jewish Italians from the deadly clutches of the Holocaust.

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.

Life is a constant struggle for the 18-year-old Nowak twins as they raise their three younger siblings in rural Poland under the shadow of the Nazi occupation. The constant threat of arrest has made everyone in their village a spy, and turned neighbor against neighbor. Though rugged, independent Helena and pretty, gentle Ruth couldn't be more different, they are staunch allies in protecting their family from the threats the war brings closer to their doorstep with each passing day.