A study in treason : a daughter of Sherlock Holmes mystery
(Book)

"When an executed original of a secret treaty between England and France, known as the French Treaty, is stolen from the country estate of Lord Halifax, Scotland Yard asks Joanna, Dr. John Watson, Jr., and Dr. John Watson, Sr. to use their keen detective skills to participate in the hunt for the missing treaty. As the government becomes more restless to find the missing document and traditional investigative means fail to turn up the culprit, Joanna is forced to devise a clever plan to trap the thief and recover the missing treaty."--,Provided by publisher.