The story is based on the real-life World War I spy ring called the Alice Network, which operated in German-occupied France and Belgium.

During a stopover in England, she slips away from her mother and tracks down World War I British spy Eve Gardiner, whose name appeared on a report Charlie's father had received when he was trying to locate Rose.

She is recruited by "Uncle Edward" (Captain Cameron) to join the Alice Network, a group of mostly female spies working against the Germans in northeastern France.

Eve conceals her fluency in German so she can eavesdrop on conversations at the restaurant and pass on valuable intelligence to Lili and her lieutenant “Violette” (Léonie van Houtte).

Upon her release at the end of the war, Eve returns to England, where she refuses to accept the medals that she was awarded for her service because she believes that she doesn't deserve them.

She lives on her pension and becomes an alcoholic, working for a time helping people locate family members during World War II.

She had contacted Violette, who was able to find out from court records that someone named Mlle Tellier had informed on Lili, so Eve was not at fault after all.

The novel is inspired by the true story of the Alice Network, a group of women spies who worked for the British during World War I in the area of Lille, France, gathering information about German troop movements and battle plans.