When the widow of a respectable Marylebone physician is found dead in her study, the police dismiss it as natural causes-a weak heart, nothing more. But Dr. John Watson knows his friend Sherlock Holmes sees what others miss: the forced window, the missing Renaissance puzzle-box, and the late woman’s journal filled with cryptic observations about hidden compartments and alchemical symbols.
The box, attributed to the enigmatic Florentine polymath Girolamo Adriani, was said to be one of only three in existence-objects rumored to hold secrets of the suppressed Black Dragon Company and connections to devices the Inquisition once deemed instruments of the devil. As Holmes investigates, he uncovers a web of forgery, obsession, and rival collectors willing to kill for Renaissance treasures.