An assassination attempt is made on Tsar Nicholas II of Russia at the Hotel Adlon in Berlin. However, the criminal police suspect that the attack was intended for Kaiser Wilhelm II of Germany, who had received the Russian guest. When Nicholas II commissions Sherlock Holmes to investigate the incident, a second assassination attempt occurs.

Shortly afterward, the itinerant preacher and spiritual healer Rasputin appears.

Holmes and Watson become entangled in the perfidious power games of two superpowers.