Hidden in the depths of eighteenth-century London, a secret apothecary shop caters to an unusual kind of clientèle. 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. Meanwhile...

Ave Maria Mulligan is the thirty-five-year-old self-proclaimed spinster of Big Stone Gap, in the Blue Ridge Mountains of Virginia. Ave Maria is content with her life of doing errands and negotiating small details - until she discovers a skeleton in her family's formerly tidy closet that completely unravels her quiet, conventional life...

In 1665 London, fourteen-year-old Christopher Rowe, apprentice to an apothecary, and his best friend, Tom, try to uncover the truth behind a mysterious cult, following a trail of puzzles, codes, pranks, and danger toward an unearthly secret with the power to tear the world apart.