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.

1929: Miss Clara Vale is a woman ahead of her time. Rather than attending Oxford to bag an eligible Duke (as her mother, Lady Vale, so desperately hoped), she threw herself into a degree in chemistry, with aspirations to become a scientist in her own right. But the world isn't ready for Clara. Unable to land a job in science because she's a woman, she is stuck behind the desk at a dingy London library. Until her estranged Uncle dies suddenly, leaving her his private detective agency, and laboratory, in his will.

Lady Emily Hardcastle is an eccentric widow with a secret past. Florence Armstrong, her maid and confidante, is an expert in martial arts. The year is 1908 and they've just moved from London to the country, hoping for a quiet life. But it is not long before Lady Hardcastle is forced out of her self-imposed retirement. There's a dead body in the woods, and the police are on the wrong scent. Lady Hardcastle makes some enquiries of her own, and it seems she knows a surprising amount about crime investigation...

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.

Recently divorced and reluctantly retired, Julia Bird has fled London to enjoy idyllic rural life in the Cotswolds. Determined to have the perfect English garden, her first job is to tear down the old shed, where she unearths much more than she’d bargained for: a body, apparently buried for decades. But who could it be, and who killed them? The police draw a blank, and even the gossip-fest that is the local book club can’t remember anyone going missing in the village.

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.

Before Jack the Ripper terrorised London, Police Inspector Samuel Ravenscroft patrolled the streets of Whitechapel. Clever and hard-working, Ravenscroft nonetheless has the worst record in the force. He lets a murderer escape during a chase and is banished to the spa town of Malvern for a water treatment to cure his asthma. Ravenscroft accepts a dinner invitation from a new acquaintance, Jabez Pitzer. Before dinner, the maid finds Pitzer slumped over his desk - dead. Ravenscroft immediately recognises the signs - Pitzer has been poisoned.

June 1933. Independent, young Kitty Underhay has been left in charge of her family’s hotel, The Dolphin, on the tranquil English coast. But when several rooms are broken into and searched, including Kitty’s own, she quickly realizes that something out of the ordinary is afoot at the hotel. Soon, rumors are flying in the cozy town that someone is on the hunt for a stolen ruby. A ruby that Kitty’s mother may well have possessed when she herself went missing during the Great War.

Lady Katherine would rather chase clues than suitors. Her reputation as a matchmaker could give her the cover she needs to follow in her detective father's footsteps. If she catches the Pink Ribbon Killer before he strikes again, she'll win her dowry and her independence in the process. One look through the exclusive Northbrooke estate house party doubles her suspect list. With the help of her trusty maid and her precocious pug, Katherine risks it all to unmask the killer. But is winning her freedom worth putting another debutante in mortal danger?