The disappearance on stage of a magician's assistant is the beginning of a case that draws Holmes and Watson into the world of international intrigue. A German pianist, a diplomat working as an aide to the Kaiser is enraged by Holmes's activities during the investigation. However, this chance meeting inadvertently saves Holmes from certain death. A secret deal struck by the British Government with an old foe threatens to tear Sherlock and Mycroft apart. Only Holmes's unique skills of observation and deduction coupled with swift action can halt a very public assassination and avert war in Europe.