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.

Cambridgeshire - March 1939. As the clouds of war begin to gather in Europe, the Talbot family of rural Blackberry Farm will be torn apart, just as so many families all over the world will be. Life will never be the same again. Whilst in London, the Salmons family will feel the pain of parting and loss. Brought together by war, the two families become intertwined and, as the outlook looks bleak, they must draw on each other’s strength to fight through the hard times.

London, 1940. Bombs fall and Josie Banks’ world crumbles around her. Her overbearing husband, Stan, is unreachable, called to service. Her home, a ruin of rubble and ash. Josie’s beloved tearoom boss has been killed, and Josie herself is injured, with nothing left and nowhere to go. Evacuated to the English countryside, Josie ends up at the estate of the aristocratic Miss Harcourt, a reluctant host to the survivors of the Blitz. Now a threat looms larger than anyone imagined. And a dangerous secret is about to upend Josie’s life again.

Gracie Thompson has a job, a loving family, a twin brother who drives her insane and a great friend. A chance meeting introduces her to the love of her life. But the storm clouds are gathering, Europe is teetering on the verge of war and threatening to destroy everything Gracie holds dear. When war arrives her family are split up, her younger siblings evacuated, her brothers join up to serve, her boyfriend, Charlie, is in daily danger and her life is threatened.

Germany, 1937. Fear and betrayal stalk the streets. People disappear. Persecution of the Jews has become a national pastime. When Ruth Friedman's husband is arrested by the SS, she is left to fend for herself and her four children. She alone stands as their shield against the Nazis. But where can she go? Where will her family be safe? Ruth must overcome the indifference, hatred and cruelty that surrounds her as she and her family race to escape the advancing Nazi army's final solution.

1941. The Blitz rages over London. And even in Cornwall, the war is being fought. When Violet loses her sister in the Blitz, she must take her nieces to safety in Cornwall. On the coast, she meets carefree chorus girl Eva, who is also running from the dangers of London. But Porthcurno hides a secret military base, and soon Violet and Eva realise there’s a battle to fight in Cornwall, too. Together with local Hazel, who works on the base, they must come together to help the war effort. But will their friendship be enough to keep them safe?

Dublin, 1952. When Mary Kate Ryan receives a surprise inheritance from the woman who abandoned her as a tiny baby, she’s stunned. All her life, she has longed to know why her mother disappeared, and now she’s devastated to realize that every lonely night she spent without a home or family of her own, her mother knew exactly where she was.

After the heartbreak of World War Two, newlywed midwife Cathy hoped Liverpool life would offer some joy. But a terrible miscarriage and the escape of her abusive stepfather Jack from prison make happiness hard to find. Meanwhile, Cathy’s beloved granny is ailing. Whilst at the hospital, Cathy sees her midwifery friends, who are planning to open a home for unmarried mothers. After losing a baby of her own, Cathy would love to help, but for now, she must take care of her grandmother.

Lina Meisel, a retired librarian in Florida, is reading the newspaper one morning when she freezes. Her eyes lock on a photograph of a book she hasn’t seen in 65 years - a book she recognizes as The Book of Lost Names. The accompanying article discusses the looting of libraries by the Nazis across Europe during World War II - an experience Lina remembers well - and the search to reunite people with the texts stolen from them so long ago. The book in the photograph is one of the most fascinating cases.

Twenty-five years after the end of the war, Noah Ainsworth is still preoccupied with those perilous, exhilarating years as a British SOE operative in France. A head injury sustained on his final operation has caused frustrating gaps in his memory—in particular about the agent who saved his life during that mission gone wrong, whose real name he never knew, nor whether she even survived the war.

Hull, 1940. Widowed Edie Copeland has just arrived on Exchange Street, heavily pregnant and with heavy suitcase in tow. She left York after tragedy struck to make a fresh start, but she's a stranger to this street, and her new landlord doesn't hesitate to remind her of this, widow or not. Luckily, the neighbours are a little more welcoming and Edie is soon made to feel at home by the Maguires and the Scuttles. As air raids sound and the war feels closer than ever, the community has to stick together. But Edie is hiding something, and she doesn't know how much longer her secret is safe.

Ava thought her job as a librarian at the Library of Congress would mean a quiet, routine existence. But an unexpected offer from the US military has brought her to Lisbon with a new mission: posing as a librarian while working undercover as a spy gathering intelligence. Meanwhile, in occupied France, Elaine has begun an apprenticeship at a printing press run by members of the Resistance. It’s a job usually reserved for men, but in the war, those rules have been forgotten. Yet she knows that the Nazis are searching for the press and its printer in order to silence them.

Hamburg, 1942. Seventeen-year-old Anna knows she can never tell her proud parents the truth about where she is going. She must hide the fact that she is pregnant, that the father of her unborn child is dead, and that she is on her way to a special maternity home, where her baby will be given to a perfect family. She tells herself that this is the best solution. She doesn’t expect to feel the rush of love for her beautiful baby boy in the white blanket or the devastation when he is snatched from her, never to be seen again.

Berlin, 1930—When a wave of change sweeps a radical political party to power, Sofie von Meyer Rhodes’s academic husband benefits from the ambitions of its newly elected chancellor. Although Sofie and Jürgen do not share the social views growing popular in Hitler’s Germany, Jürgen’s position with its burgeoning rocket program changes their diminishing fortunes for the better. But as Sofie watches helplessly, her beloved Berlin begins to transform, forcing her to consider what they must sacrifice morally for their young family’s security, and what the price for their neutrality will be.

In a different world, Evie Milton would have accepted her fate, married an aristocrat and become the doyenne of one of England’s finest estates, just like her mother. In a different world, Rose Wiley would have married her fiancé, David, established a modest homestead and brought up a brood of babies, just like her mother. But this isn’t a different world, and these women are not their mothers. Rose dreams of a life filled with more than family and duty to her husband—a life of purpose—and Evie dreams of a life far away from her rarefied existence.