Let the wicked be ashamed, and let them be silent in the grave. These ominous words, slashed from the pages of a book of Psalms, are the last threat that the darling of London society, Sir Edward Grey, receives from his killer. Before he can show them to Nicholas Brisbane, the private inquiry agent he has retained for his protection, Sir Edward collapses and dies at his London home, in the presence of his wife, Julia, and a roomful of dinner guests.

Billie, Mary Alice, Helen, and Natalie have worked for the Museum, an elite network of assassins, for 40 years. Now their talents are considered old-school and no one appreciates what they have to offer in an age that relies more on technology than people skills.

As the city prepares to celebrate Queen Victoria's golden jubilee, Veronica Speedwell is marking a milestone of her own. After burying her spinster aunt, the orphaned Veronica is free to resume her world travels in pursuit of scientific inquiry - and the occasional romantic dalliance. As familiar with hunting butterflies as she is fending off admirers, Veronica wields her butterfly net and a hatpin with equal aplomb, and with her last connection to England gone, she intends to embark upon the journey of a lifetime.

India Steele is desperate. Her father is dead, her fiancé took her inheritance, and no one will employ her, despite years working for her watchmaker father. Indeed, the other London watchmakers seem frightened of her. Alone, poor, and at the end of her tether, India takes employment with the only person who’ll accept her–an enigmatic and mysterious man from America. A man who possesses a strange watch that rejuvenates him when he’s ill.

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.