In 1944, American naval officer Lt. Wyatt Paxton arrives in London to prepare for the Allied invasion of France. He works closely with Dorothy Fairfax, a "Wren" in the Women's Royal Naval Service. Dorothy pieces together reconnaissance photographs with thousands of holiday snapshots of France - including those of her own family's summer home - in order to create accurate maps of Normandy. Maps that Wyatt will turn into naval bombardment plans. As the two spend concentrated time together in the pressure cooker of war, their deepening friendship threatens to turn to love.

Numbed by grief and harboring shameful secrets, Lt. Adler Paxton ships to England with the US 357th Fighter Group in 1943. Determined to become an ace pilot, Adler battles the German Luftwaffe in treacherous dogfights in the skies over France. Violet Lindstrom wanted to be a missionary, but for now she serves in the American Red Cross, where she arranges entertainment for the men of the 357th in the Aeroclub on base. Drawn to the mysterious Adler, she enlists his help with her work and urges him to reconnect with his family after a long estrangement.

Major Jack Novak has never failed to meet a challenge - until he meets army nurse Lieutenant Ruth Doherty. When Jack lands in the army hospital after a plane crash, he makes winning Ruth's heart a top priority mission. But he has his work cut out for him. Not only is Ruth focused on her work in order to support her orphaned siblings back home, she carries a shameful secret that keeps her from giving her heart to any man. Can Jack break down her defenses? Or are they destined to go their separate ways?

Lt. Raymond Novak prefers the pulpit to the cockpit, but at least his stateside job training B-17 pilots allows him the luxury of a personal life. As he courts Helen Carlisle, a young war widow and mother who conceals her pain under a frenzy of volunteer work, the sparks of their romance set a fire that flings them both into peril. After Ray leaves to fly a combat mission at the peak of the air war over Europe, Helen takes a job in a dangerous munitions yard and confronts an even graver menace in her own home. 

Lt. Mellie Blake is looking forward to beginning her training as a flight nurse. She is not looking forward to writing a letter to a man she’s never met - even if it is anonymous and part of a morale-building program. Lt. Tom MacGilliver, an officer stationed in North Africa, welcomes the idea of an anonymous correspondence - he’s been trying to escape his infamous name for years. As their letters crisscross the Atlantic, Tom and Mellie develop a unique friendship despite not knowing the other’s true identity. When both are transferred to Algeria, the two are poised to meet face-to-face for the first time.

Once London's top thief, Barclay Pearce has turned his back on his life of crime and now uses his skills for a nation at war. But not until he rescues a clockmaker's daughter from a mugging does he begin to wonder what his future might hold. Evelina Manning has constantly fought for independence, but she certainly never meant for it to inspire her fiance to end the engagement and enlist in the army. When the intriguing man who saved her returns to the Manning residence to study clockwork repair with her father, she can't help being interested.

Present day, London: When Sophie discovers a photograph of her great aunt Vivi from World War II, it throws her into a world of confusion. Because, as she learns about this secret relative, she quickly realizes that the photograph doesn’t fit with her family’s story. It shows Vivi leaving an address associated with a spy network in London - a place she had no reason to be - and it is dated right before she disappeared. 

Willa Forsythe is both a violin prodigy and top-notch thief, which makes her the perfect choice for a crucial task at the outset of World War I - to steal a cypher from a famous violinist currently in Wales. Lukas De Wilde has enjoyed the life of fame he's won - until now, when being recognized nearly gets him killed. Everyone wants the key to his father's work as a cryptologist. And Lukas fears that his mother and sister, who have vanished in the wake of the German invasion of Belgium, will pay the price. The only light he finds is meeting the intriguing Willa Forsythe.

A heart-wrenching, poignant and totally unforgettable tale of a young woman who must finally face up to the secret she has hidden for a lifetime. 1943, England: On a foggy night during the blackout, 25-year-old May Robinson watches in horror as her mother, Ivy, is tragically killed. Heartbroken, May is not sure she has the strength to harbour the secret she has kept for so many years - a secret that her mother devoted her life to hiding and that would tear their broken family even further apart.

Three years into the Great War, England's greatest asset is their intelligence network - field agents risking their lives to gather information, and codebreakers able to crack every German telegram. Margot De Wilde thrives in the environment of the secretive Room 40, where she spends her days deciphering intercepted messages. But when her world is turned upside down by an unexpected loss, for the first time in her life numbers aren't enough.