Showing The Game by Laurie R. King

New Year 1924. Mary Russell is drawn into a new intrigue when she and her husband, Sherlock Holmes, pay a visit to Holmes' gravely ill brother, Mycroft. Mycroft has received a strange package that contains the papers of a missing English spy named Kimball O'Hara, the hero of Rudyard Kipling's Kim, who is feared to have been taken hostage.