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.

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?

Never pretty enough to please her gorgeous mother, Allie will do anything to gain her approval - even marry a man she doesn't love. Lt. Walter Novak - fearless in the cockpit but hopeless with women - takes his last furlough at home in California before being shipped overseas. Walt and Allie meet at a wedding and their love of music draws them together, prompting them to begin a correspondence that will change their lives. As letters fly between Walt's muddy bomber base in England and Allie's mansion in an orange grove, their friendship binds them together. 

It is 1939, and working-class Evie Bishop has received a scholarship to study mathematics at Oxford when tragedy turns her life upside down. Evie must seek a new future for herself and, inspired to contribute to the war effort, joins the Women’s Auxiliary Air Force as an Ops Room plotter. Posted to a fighter station on the Sussex Coast, Evie befriends two other WAAFs. But the German bombers seem to know more than they should about the base’s operations, and soon Evie, May and Jess are caught up in a world more dangerous than they ever imagined. 

All of England thinks Phillip Camden a monster - a man who deliberately caused the deaths of his squadron. But as nurse Arabelle Denler watches the so-dubbed "Black Heart" every day, she sees something far different: a hurting man desperate for mercy. And when their paths twist together and he declares himself her new protector, she realizes she has her own role to play in his healing.

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.

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.

The hedonism of London in the Roaring Twenties is a world away from Annabel Tarleton's ordinary country existence. Until a chance meeting with the charming Richard Hansen at a society ball changes her life for ever. Annabel finds herself trapped inside a marriage that behind closed doors is cruel. Annabel has no choice but to flee and will do everything to save herself and her unborn baby. But the very powerful expect to get what they want....