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....

London, 1941: Miss Jane Treen is at her desk, strong black coffee in hand and fluffy ginger cat by her side, when her top-secret government work is interrupted by an urgent call to Devon. A woman has been found dead in a lake in a place where she shouldn’t have been. Jane needs to gather the clues and find the killer before someone else from the agency gets hurt… Shy and handsome code-breaker Arthur Cilento is bewildered by the arrival of the efficient Miss Treen and her cat Marmaduke.

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...

The king's magnificent palace was built in a matter of weeks. No one saw the builders, no villagers are allowed beyond the gilded gate, and only one servant has ever left. The haunted look in her eyes as she was recaptured by the palace guards is something Josie, daughter of the village doctor, has never forgotten. For Josie, the palace is a mystery that grows more intriguing after she meets the captain of the guards, a man known only as Hammer, as mysterious and captivating as the palace itself. Whispers of magic fuel Josie's desire to uncover the truth, but an ordinary girl like her can only dream of ever being invited inside.

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.