What a fun mystery! Two American children, Xena Holmes, 12, and her brother, Xander, 10, have just arrived in London and are settling in, when they find out that they are the great-great-great-grandchildren of Sherlock Holmes. They inherit his notebook of unsolved cases, and it turns out they've also inherited his sleuthing talent! And Watson's great-great-great-grandson, Andrew Watson, plays an important part in solving the case they're working on, which involves the whereabouts of a valuable painting that went missing more than 100 years ago.
In addition to the mystery plot itself, I enjoyed the Sherlockian lore woven throughout the story, the setting, the lively characters, and the way Xena and Xander learn the differences between British and American English (e.g., "biscuits" for "cookies," "football" for "soccer"). Reading this series just may inspire kids to go on to the original tales by Arthur Conan Doyle.