The Blue Diamond

221b Baker St. is home to a new generation, with Sherlock Holmes’s daughter, Joanna, and her husband, Dr. John Watson Jr., son of Sherlock’s longtime sidekick, in residence and solving crimes. In this sixth in the series, Joanna, who’s just as meticulous and insightful as her father, is called by Scotland Yard to help with a series of thefts in hotels around London. Joanna wonders why she and the Yard are required until she learns that the victim of the most recent crime is the governor general of South Africa, and what was stolen from his locked room was the enormously valuable blue diamond, the search for which sets the Watsons questioning everyone from diamond merchants to underworld dealers. In addition, it’s 1917, and the detectives must pursue another stolen item, one that’s crucial to the British effort to win the Great War. This part of the plot sees the famous offspring draw on every ounce of their courage as well as their connections with Sherlock’s Baker St. Irregulars, a gang of ruffian children, to win the day. Along the way, readers will enjoy the many references to Sherlock Holmes’s cases, often the subject of reminiscences by his daughter and her father-in-law; also a pleasure is the relationship between Joanna and John, she a wily sleuth and he an adoring supporter of her eccentricities. For fans of the great detective, of course, but also those who enjoy tales of wartime espionage.