Alix St. Pierre. An unforgettable name for an unforgettable woman. She grew up surrounded by Hollywood glamor, but, as an orphan, never truly felt part of that world. In 1943, with WWII raging and men headed overseas to fight, she lands a publicity job to recruit women into the workforce. Her skills—persuasion, daring, quick-witted under pressure—catch the attention of the U.S. government and she finds herself with an even bigger assignment: sent to Switzerland as a spy. Soon Alix is on the precipice of something big, very big. But how far can she trust her German informant…?

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.

1938. Dr. Ho Fengshan, consul general of China, is posted in Vienna with his American wife, Grace. Shy and ill at ease with the societal obligations of diplomats’ wives, Grace is an outsider in a city beginning to feel the sweep of the Nazi dragnet. When Grace forms a friendship with her Jewish tutor, Lola Schnitzler, Dr. Ho requests that Grace keep her distance. His instructions are to maintain amicable relations with the Third Reich, and he and Grace are already under their vigilant eye.

Clara Button is no ordinary librarian. While war ravages the city above her, Clara has risked everything she holds dear to turn the Bethnal Green tube station into the country’s only underground library. Down here, a secret community thrives with thousands of bunk beds, a nursery, a café, and a theater—offering shelter, solace, and escape from the bombs that fall upon their city. Along with her glamorous best friend and assistant Ruby Munroe, Clara ensures the library is the beating heart of life underground. As the war drags on, the women's determination is tested to the limits.

For months, Marianne’s resistance network has carried out courageous missions from a remote farmhouse in Southern Provence, aiding the Nazis’ downfall. But one fateful night, they are viciously ambushed as German soldiers storm in, scattering, capturing or killing every last person there. Mourning the loss of her friends, Marianne will need every ounce of courage to survive. Not only has her life as a secret agent been critically compromised, but her heart has been shattered. Because Jack, her darling fiancé and fellow spy, fled in the chaos–and is accused of being a traitor.