The Valley of Fear is the fourth and final Sherlock Holmes novel by Sir Arthur Conan Doyle. Scotland yard officer Mr. Mcdonald seeks the help of Sherlock Holmes of solve mystery around discovery of a Dead Body, resembling Birlstone's owner Mr. Douglas. Holmes decodes a cipher warning from Moriarity's Organization, he also guddes the missing dumb-well weighted down the killers clothes in the moat. After a number of twists and turns he tries to solve the mystery.