When a murder is committed, a lady's companion finds herself in the role of amateur sleuth...1789, London: When Emily Fanshawe, Marchioness of Polbrook, is found strangled in her bedchamber, suspicion immediately falls on those residing in the grand house in Hanover Square. Emily's husband - Randal Fanshawe, Lord Polbrook - fled in the night and is chief suspect - much to the dismay of his family. Ottilia Draycott is brought in as the new lady's companion to Sybilla, Dowager Marchioness, and soon finds herself assisting younger son Lord Francis Fanshawe in his investigations.

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.

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?

Newly returned from finishing school, Lady Juliette Thorndike is ready to debut in London society. Due to her years away, she hasn't spent much time with her parents, and sees them only as the flighty, dilettante couple the other nobles love. But when they disappear, she discovers she never really knew them at all. They've been living double lives as government spies-and they're only the latest in a long history of espionage that is the family's legacy.

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.