As the plague decimates London in 1665 and an assassin threatens the apothecary's life, apprentice Christopher Rowe and his faithful friend Tom, following a trail of puzzles, riddles, and secrets, risk their lives to untangle the heart of a dark conspiracy.

Raffa Santana is a healer, not a fighter. As a gifted apothecary, he has amazing instincts for unleashing the potential of magical-seeming plants. But his skills have failed to free the animals that the heartless Chancellor captured and turned against the people of Obsidia directly threatening Raffa's friends and family.

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.