Three very different women are recruited to the mysterious Bletchley Park, where the best minds in Britain train to break German military codes. Vivacious debutante Osla has the dashing Prince Philip of Greece sending her roses – but she burns to prove herself as more than a society girl, working to translate decoded enemy secrets. Self-made Mab masters the legendary codebreaking machines as she conceals old wounds and the poverty of her East-End London upbringing. And shy local girl Beth is the outsider who trains as one of the Park’s few female cryptanalysts.

Paris, 1943: Lana Antanova is rushing to tell her husband she is pregnant when she witnesses him being executed by a Gestapo officer for hiding a Jewish girl in a piano. Overcome with grief, Lana loses the baby. A few months later, a heartbroken Lana is approached to join the Resistance on the French Riviera. As the daughter of a Russian countess, Lana has the perfect background to infiltrate the émigré community of Russian aristocrats who socialise with Nazi officers, including the man who killed her husband.

As Hitler’s bombs rain down on a battered and beleaguered Britain, Ruby Shadwell is dealt the most devastating blow - her entire family lost during the Coventry Blitz. Alone and with the city in chaos, Ruby is determined to survive this war and rebuild her life. And a chance encounter with street urchin Tommy gives Ruby just the chance she needs. Because Tommy brings with him Canadian Sergeant Jean-Paul Clayton.

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. 

September 1940. As the bombs of the Blitz fall on London, Ruby and Stevie are falling in love. United by a shocking experience when they were evacuees, Ruby believes that she understands Stevie like nobody else can. But then Stevie is sent abroad into danger, and as Ruby waits desperately for letters with foreign stamps that never come, she begins to fear that he is lost forever. And when Stevie does return, he has changed, and Ruby faces a difficult choice. 

When Caroline Williams wakes up in a hospital bed in Paris with no memory of her past, she finds that returning to the life she has forgotten is harder than she thought. Especially as her feet seem to know where to go and her cavernous apartment seems devoid of any memories...Taking her mind off her foggy past is the discovery of a stack of World War Two love letters written by a young mother named Celine to her beloved, Luc, found in a box in the spare room.

It’s February 1942, and as the Americans finally join Britain and her allies, 23-year-old Francesca Fabrino is doing her bit for the war effort in a factory in East London. But her thoughts are constantly occupied by recently married Charlie Brogan, who is fighting in North Africa with the Eighth Army. When Francesca starts a new job for the BBC Overseas department, she meets handsome Count Leo D’Angelo and begins to put her hopeless love for Charlie aside. 

With her family struggling amidst the nightly bombing raids in London’s East End, Ida Brogan is doing her very best to keep their spirits up. The Blitz has hit the Brogans hard, and rationing is more challenging than ever, but they are doing all they can to help the war effort. When Ida’s oldest friend Ellen returns to town, sick and in dire need of help, it is to Ida that she turns. But Ellen carries a secret, one that threatens not only Ida’s marriage but the entire foundation of the Brogan family. Can Ida let go of the past and see a way to forgive her friend? 

Fourteen-year-old Dita is one of the many imprisoned by the Nazis at Auschwitz. Taken, along with her mother and father, from the Terezín ghetto in Prague, Dita is adjusting to the constant terror that is life in the camp. When Jewish leader Freddy Hirsch asks Dita to take charge of the eight precious volumes the prisoners have managed to sneak past the guards, she agrees. And so, Dita becomes the librarian of Auschwitz.

March, 1942: new mother Alice Milward is itching to return to her job as a shop assistant at Liberty’s. Despite her husband still being missing in action, Alice is determined to give baby Arthur the best possible start. She soon settles back into the rhythm of life on the shop floor, and the Liberty Girls rally to help keep everything on an even keel. But when the American GIs start swarming into London, there are more complications to come. And each of the Liberty Girls has their own impossible storm to weather.