In December of 1912, at the London Geology Conference, a fake ape-man fossil, composed of an ape's jaw and part of a human skull, was presented as evidence of a newly discovered species of prehistoric man, named "Piltdown Man" for the site of its purported discovery in England. The hoax was a distraction to science for over forty years, and an embarrassment to anthorpology when modern analysis exposed the fakery. Sherlockian scholars have long wondered at the singular omission of the infamous Piltdown hoax from the chronicals of Dr. Watson. Did Sherlock Holmes investigate and fail to discover the truth? If he discovered the truth, why did he not expose it at the time? New evidence indicates that Holmes DID learn of the hoax. Why he kept it secret is a sinister tale of grisly murders, weird intrigues, and the arcane politics of a Europe bent on rushing madly toward what historians would call World War One. Holmes and Watson risked death following a trail of clues to a fantastic plot to use the London Conference in a scheme to unseat the crowned heads of Europe. Holmes detected the hand of Professor Moriarty behind the scenes, and finally had Moriarty in his revolver sights.