Hidden in the depths of eighteenth-century London, a secret apothecary shop caters to an unusual kind of client�ele. Women across the city whisper of a mysterious figure named Nella who sells well-disguised poisons to use against the oppressive men in their lives. But the apothecary's fate is jeopardized when her newest patron, a precocious twelve-year-old, makes a fatal mistake, sparking a string of consequences that echo through the centuries....

Back when Harry Bosch was just a rookie homicide detective, he had an inspiring mentor who taught him to take the work personally and fight for for every case. Now that mentor, J.J. Thompson, is dead, but after his funeral his widow hands Bosch a murder book that Thompson took - outlining the unsolved killing of a troubled young man. Bosch brings the murder book to Renee Ballard and asks her to help him find what about the case lit Thompson's fire...