Rare-book dealer Ashlyn Greer’s affinity for books extends beyond the intoxicating scent of old paper, ink, and leather. She can feel the echoes of the books’ previous owners—an emotional fingerprint only she can read. When Ashlyn discovers a pair of beautifully bound volumes that appear to have never been published, her gift quickly becomes an obsession. Not only is each inscribed with a startling incrimination, but the authors, Hemi and Belle, tell conflicting sides of a tragic romance.

1944, Rome. Newlywed Niki Novotná is recruited by a new American spy agency to establish a secret branch in Italy's capital. One of the OSS's few female operatives abroad and multilingual, she's tasked with crafting fake stories and distributing propaganda to lower the morale of enemy soldiers. Despite limited resources, Niki and a scrappy team of artists, forgers and others—now nicknamed The Lipstick Bureau—find success, forming a bond amid the cobblestoned streets and storied villas of the newly liberated city.

1942: With the war's outcome hanging in the balance, President Roosevelt sends an unlikely new taskforce on a unique mission. They are librarians and microfilm specialists trained in espionage, working with a special branch of the Office of Strategic Services and deployed to neutral cities throughout Europe. By acquiring and scouring Axis newspapers, books, technical manuals, and periodicals, the librarians can gather information about troop location, weaponry, and military plans.

London, 1940. Britain is gripped by the terror of the Blitz, forcing Nell Spelman to flee the capital with her young daughter - leaving behind her husband, Arthur, the clockmaker who keeps Big Ben chiming. When Arthur disappears, Nell is desperate to find him. But her search will lead her into far darker places than she ever imagined.

Left with an estate on the brink of bankruptcy after their father's death, Lady Marigold Fairfax and her brother open a private investigation firm marketed to the elite . . . to spy on the elite. Dubbed The Imposters, Ltd., their anonymous group soon becomes the go-to for the crème of society when they want answers delivered surreptitiously. But the many secrets Marigold learns about her peers pale in comparison to her shock when she and her brother are hired to investigate her best friend's father as a potential traitor.

Rhoda Middleton suspects her husband Peter is having an affair. But when Rhoda tracks the mysterious woman down, she finds she is not his lover after all, but the wife of his wartime best friend, Archie Foster. There is only one problem - Rhoda has never even heard of Archie Foster.

At the end of her first unsuccessful season out in society, Lady Georgiana has all but given up on attracting a suitable man - until she receives an invitation to a masked Halloween ball at Broxley Manor. Georgie is uncertain why she was invited, until she learns that the royal family intends to marry her off to a foreign prince, one reputed to be mad.

Londoner Madeleine Grant is studying at the Sorbonne in Paris when she marries charismatic French journalist Giles Martin. As they raise their son, Olivier, they hold on to a tenuous promise for the future. Until the thunder of war sets off alarms in France. Staying behind to join the resistance, Giles sends Madeleine and Olivier to the relative safety of England, where Madeleine secures a job teaching French at a secondary school. Yet nowhere is safe. After a devastating twist of fate resulting in the loss of her son, Madeleine accepts a request from the ministry to aid in the war effort.

In the snowbound city of Kiev, wry and bookish history student Mila Pavlichenko organizes her life around her library job and her young son—but Hitler’s invasion of Russia sends her on a different path. Given a rifle and sent to join the fight, Mila must forge herself from studious girl to deadly sniper—a lethal hunter of Nazis known as Lady Death. When news of her three hundredth kill makes her a national heroine, Mila finds herself torn from the bloody battlefields of the eastern front and sent to America on a goodwill tour.

Between the World Wars, the six Mitford sisters—each more beautiful, brilliant, and eccentric than the next—dominate the English political, literary, and social scenes. Though they've weathered scandals before, the family falls into disarray when Diana divorces her wealthy husband to marry a fascist leader and Unity follows her sister's lead all the way to Munich, inciting rumors that she's become Hitler's mistress.

London, 1941. The Blitz. When a Royal Navy memo arrives at head office, requesting female recruits to sign up as motorcycle dispatch riders, delivering highly classified orders across the country, three women jump at the chance to sign up for the most dangerous jobs in London.

Sophie Dix fled Stuttgart with her brother as the Nazi regime gained power in Germany. Now, with her brother gone and her adopted home city of Paris conquered by the Reich, Sophie reluctantly accepts a position restoring damaged art at the Jeu de Paume museum under the supervision of the ERR—a German art commission using the museum as a repository for art they’ve looted from Jewish families.

American Josie Anderson and Parisian Arlette LaRue are thrilled to be working in the French resistance, stealing so many Nazi secrets that they become known as the Golden Doves, renowned across France and hunted by the Gestapo. Their courage will cost them everything. When they are finally arrested and taken to the Ravensbrück concentration camp, along with their loved ones, a reclusive Nazi doctor does unspeakable things to Josie’s mother, a celebrated Jewish singer who joined her daughter in Paris when the world seemed bright. And Arlette’s son is stolen from her, never to be seen again.

Ana Kaminski is pushed through the iron gates of Auschwitz beside her frightened young friend Ester Pasternak. As they reach the front of the line, Ana steps forward and quietly declares herself a midwife--and Ester her assistant. Their arms are tattooed and they’re ordered to the maternity hut. Holding an innocent newborn baby, Ana knows the fate of so many are in her hands and vows to do everything she can to save them.

Paris, 1939: The Nazis think Éliane can't understand German. They’re wrong. They think she’s merely cataloging art in a Louvre museum and unaware they’re stealing national treasures for their private collections. They have no idea she’s carefully decoding their notes and smuggling information to the Resistance. But Éliane is playing a dangerous game. Does she dare trust the man she once loved with her secrets, or will he only betray her once again?