Mary Russell and Sherlock Holmes have returned home to Sussex in order to enjoy the new year, but soon enough they travel to London to visit Holmes’ brother, Mycroft, whose health is not the best. While there he suggests that perhaps they might look into a case for him. A possibly-missing person. In India.
Of course they head off, and the person they are looking for, none other than Kimball O’Hara, known to many from Rudyard Kipling’s Kim.