When Sherlock Holmes receives a coded warning from one of Moriarty' s lieutenants, he is drawn into a grisly murder in Sussex, which only he can solve. The killing has its origins in a 13-year-old conspiracy involving a secret society in America and the beginning of Holmes' s battle against the criminal organization of the evil Professor Moriarty. The Valley of Fear, originally published in 1915, was the fourth and final Sherlock Holmes novel by Arthur Conan Doyle.