England. 1923. After a year away at finishing school where she learned etiquette, deportment, and the difference between a fish fork and a salad one, Kitty Worthington is eager to return home. But minutes after she and her brother Ned board the Golden Arrow, the unthinkable happens. A woman with a mysterious connection to her brother is poisoned, and the murderer can only be someone aboard the train. When Scotland Yard hones on Ned as the main suspect, Kitty sets out to investigate.

England, 1925. When a strange young woman is found murdered on the grounds of Unsworth Castle, the duke and his family are astounded at first, but quickly become enraged when the police begin asking all sorts of impertinent questions. And when suspicions dare to fall on one of their own, it is up to Mr. Quayle, Lord Unsworth's exceedingly efficient secretary, to find the true culprit and save the House of Unsworth from scandal and ruin.

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.

Cressida Fawcett is heading to the English countryside for a weekend of cocktails and partying at her friend’s glamorous mansion, the location of a recent diamond heist. But just hours after her arrival, Cressida is woken by an almighty scream. Rushing to the landing, she looks down into the great hall to find a trembling maid standing next to the body of Harry, the friendly young chandelier cleaner. Everyone believes Harry’s death was an accident. But as Cressida examines the opulent hall and the beautiful grounds, she thinks something darker is afoot.

Frances Wynn, the American-born Countess of Harleigh, enjoys more freedom as a widow than she did as a wife. After an obligatory year spent mourning her philandering husband, Reggie, she puts aside her drab black gowns, leaving the countryside and her money-grubbing in-laws behind. With her young daughter in tow, Frances rents a home in Belgravia and prepares to welcome her sister, Lily, arriving from New York - for her first London season.

December 1899. After the death of her beloved grandmother, Cleopatra Fox moves into the luxury hotel owned by her estranged uncle in the hopes of putting hardship and loneliness behind her. But the poisoning of a guest on Christmas eve throws her new life, and the hotel, into chaos. Cleo quickly realizes no one can be trusted, not Scotland Yard and especially not the hotel’s charming assistant manager.

Edinburgh, 1911: When Maud McIntyre and her lady’s maid, Daisy, form a detective agency, they never dream their first case will take place at a glamorous house in the Scottish Highlands. But when the duchess of Duddingston, concerned that a notorious jewelry thief will target her lavish weekend party, employs Maud to go undercover as a guest to find the culprit, the agency has its first case to solve....

Her beauty almost certainly saved her from the rising Nazi party and led to marriage with an Austrian arms dealer. Underestimated in everything else, she overheard the Third Reich's plans while at her husband's side, understanding more than anyone would guess. She devised a plan to flee in disguise from their castle, and the whirlwind escape landed her in Hollywood. She became Hedy Lamarr, screen star.

A reluctant ex-spy with demons of her own, Elinor finds herself facing down one of the most dangerous organized crime gangs in London, ultimately exposing corruption from Scotland Yard to the highest levels of government. The private, quiet “Miss White" as Elinor is known, lives in a village in rural Kent, England, and to her fellow villagers seems something of an enigma. Well she might, as Elinor occupies a "grace and favor" property, a rare privilege offered to faithful servants of the Crown for services to the nation.

The year is 1920: Flying in the face of convention, legendary American adventuress Beryl Helliwell never fails to surprise and shock. The last thing her adoring public would expect is that she craves some peace and quiet. The humdrum hamlet of Walmsley Parva in the English countryside seems just the ticket. And, honestly, until America comes to its senses and repeals Prohibition, Beryl has no intention of returning stateside and subjecting herself to bathtub gin.

London, 1923. Newly minted research assistant Saffron Everleigh is the first woman to hold the position at University College of London. When she attends a dinner party for the school, she expects to engage in conversations about the university's large expedition to the Amazon. What she doesn’t expect is for Mrs. Henry, one of the professors’ wives, to drop to the floor, poisoned by an unknown toxin. Dr. Maxwell, Saffron’s mentor, is the main suspect, and evidence quickly mounts.

Librarian Sylvia Ashe knows nothing about her past, having grown up without a father and a mother who refused to discuss him. When she stumbles upon a diary that suggests she's descended from magicians, she's skeptical. After all, magicians are special, and she's just an ordinary woman who loves books. She seeks answers from a member of the most prominent family of magicians, but she quickly learns that finding the truth won't be easy, especially when he turns out to be as artless as her, and more compelling and dangerous than books.

England, 1920. Eleanor Swift has spent the last few years travelling the world: taking tea in China, tasting alligators in Peru, escaping bandits in Persia and she has just arrived in England after a chaotic 45-day flight from South Africa. Chipstone is about the sleepiest town you could have the misfortune to meet. But then, from the edge of a quarry, through the driving rain, Eleanor is shocked to see a man shot and killed in the distance. Before she can climb down to the spot, the villain is gone and the body has vanished.

Molly Murphy always knew she'd end up in trouble, just as her mother predicted. So, when she commits murder in self-defense, she flees her cherished Ireland, under cover of a false identity, for the anonymous shores of late 19th-century America. When she arrives in New York and sees the welcoming promise of freedom in the Statue of Liberty, Molly begins to breathe easier. But when a man is murdered on Ellis Island, a man Molly was seen arguing with, she becomes a prime suspect in the crime.

Why did Agatha Christie spend her career pretending that she was "just" an ordinary housewife, when clearly she wasn't? Lucy Worsley's biography is not just of a massively, internationally successful writer. It's also the story of a person who, despite the obstacles of class and gender, became an astonishingly successful working woman. With access to rarely seen personal letters and papers, Lucy Worsley's biography is both authoritative and entertaining and makes us realize what an extraordinary pioneer Agatha Christie was—truly a woman who wrote the twentieth century.