The Adventure of the Peerless Peer

The ”Peerless Peer” of the title is none other than Lord Greystoke, the jungle-born scion of a noble English family, a duke in Britain but in his larger estate of Central Africa a king. The time is 1916, at the height of the Great War. The east wind has grown appallingly cold in England, and when the Foreign Office learns that a deadly formula has been stolen from the Allies by Sherlock Holmes' old foe, the German agent Von Bork, Mycroft calls his younger brother out of retirement to save the Empire from the greatest danger that ever threatened it. Watson, of course, accompanies Holmes on this perilous mission, and his account of their adventure is one of the most thrilling narratives the good doctor ever penned.

Now re-published by Titan Books in 2011 as part of "The Further Adventures of Sherlock Holmes" series as "The Peerless Peer"