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.

August 1920, Dublin, Ireland: A fraught task keeps Verity and her husband Sidney in the country after their initial clandestine mission has been completed: the traitor Lord Ardmore is scheming to employ the deadly phosgene gas he's stolen for some terrifying purpose, and the couple will need both the Crown forces and the rebels' help to thwart him. As they pursue their quarry, they are drawn into a case involving a series of cunning and brazen jewel thefts.

Following the death of her husband, Lady Darby has taken refuge at her sister's estate, finding solace in her passion for painting. But when one of the house guests is murdered, her brother-in-law asks her to aid the insufferable Sebastian Gage - a fellow guest with some experience as an inquiry agent. While Gage is clearly more competent than she first assumed, Kiera isn't about to let her guard down, as accusations and rumors swirl.

Determined to find the men responsible for her disgraced father's murder, Lady Arianna Hadley disguises herself as a man and contrives to be hired as a chef in one of London's aristocratic households. But when the prince regent is poisoned by Arianna's special chocolate dessert, she finds her own quest has become intertwined with a far more deadly intrigue. The earl of Saybrook is asked by the government to investigate. When someone tries to kill them both, they become reluctant allies in the hunt to discover what evil is afoot.

March 1833. Kiera and her husband, Sebastian Gage, have decided to settle in Edinburgh for the winter with their infant daughter. This also allows Kiera to enjoy long hours painting in her studio, making progress on the portraits she soon hopes to unveil in her own exhibit. She's thrilled when she receives an invitation to the auction of the late Lord Eldin's coveted art collection, and she and Gage eagerly accept. When the floor collapses beneath the gathering, killing one of their fellow bidders, Kiera and Gage are lucky to escape with their lives.

Tabitha, Lady Chesterton, the Countess of Pembroke, is newly widowed at only 22 years of age. With no son to inherit the title, it falls to a dashing, distant cousin of her husband's, Jeremy Chesterton, known as Wolf. It quickly becomes apparent that Wolf had consorted with some of London's most dangerous citizens before inheriting the title. Can he leave this world behind, or will shadowy figures from his past follow him into his new aristocratic life in Mayfair? And can Tabitha avoid being caught up in Wolf's dubious activities?

It’s 1924, and Blix Windway has made a career out of her wanderlust, giving lectures to ladies’ groups about everything from the flora of the American desert to the beauty of the Swiss Alps, but she needs new material for her talks. She strikes what seems to be an ideal agreement with an eccentric older lady. Blix will be her travel companion during a journey to Egypt, helping to smooth the way through customs and coordinate sightseeing tours.

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.

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.

London, 1861. Samantha Kingston has lived under the control of her overbearing uncle since the death of her parents six years ago. Trapped by the conventions of her gender and social class, she is desperate to find a way out. But when her aunt and uncle are murdered, the freedom she sought seems even further out of reach. A suspect in the crime, she finds herself on the run, unsure whom to trust, lost in the underworld she had only ever read about in the pages of a Dickens novel.

A murdered opera singer. A duke drenched in her blood. For Bow Street Officer Hugh Marsden, the brutal killing is a straightforward case. Ever since his exile from polite society, the chance to arrest a high and mighty peer of the realm has never presented itself. Hugh won't snub the opportunity now. But Audrey Sinclair, the Duchess of Fournier, is certain her husband is wrongly accused, and she's determined to prove it to the arrogant Bow Street officer, even if she must employ her most peculiar ability—or perhaps curse—to guide her investigation. After all, a duchess can do as she pleases.

Spring, 1905: Free-spirited like the Thoroughbreds she rides across the Kentucky countryside, Stella takes adventure by the reins when she's asked to attend a mysterious wedding in rural England. But once she arrives at the lush Morrington Hall estate, her cold and ambitious father confesses that he won't only give away his best racehorses as gifts - he has also arranged to give away his daughter as bride to the Earl of Atherly's financially strapped son. Stella refuses to be sold off like a prized pony. Yet despite a rough start, there's something intriguing about her groom-to-be.

Philadelphia, 1921. When Edie Shippen returns home after spending years in California recovering from Influenza, she's shocked to discover that her childhood sweetheart is engaged to her twin sister. Heartbroken and adrift, Edie vows to begin living her life as a modern woman—and to hell with anyone who gets in her way. But as young women start to disappear from the city, her newfound independence begins to feel dangerous.

The Earl of Wrexford possesses a brilliant scientific mind, but boredom and pride lead him to reckless behavior. He does not suffer fools gladly. So when pompous, pious Reverend Josiah Holworthy publicly condemns him for debauchery, Wrexford unsheathes his rapier-sharp wit and strikes back. As their war of words escalates, London's most popular satirical cartoonist, A. J. Quill, skewers them both.

1915, London: Working in the dusty bookshop that her Aunt Violet mysteriously inherited, Hannah Merrill is accustomed to finding twists in every tale. But discovering her beloved best friend Lily-Anne – with a paperknife through her heart – in the middle of the bookshop, is not a plotline she saw coming. The case is anything but textbook. With the discovery of a coded German message, and Hannah’s instinct that Lily-Anne’s husband is keeping secrets, she determines to get to the bottom of it. She can’t do it alone though.