The Valley of Fear

The Valley of Fear is the final novel in the Sherlock Holmes series by Sir Arthur Conan Doyle. The story originally appeared over several issues of the monthly Strand Magazine in late 1914 before being published as a standalone work. While Doyle would continue to publish Sherlock Holmes short stories until 1927, The Valley of Fear remains Holmes' final long-form appearance.
In the novel, Holmes and his assistant Watson are called to assist with an investigation into the murder of John Douglas, a man shot in his own home at point-blank range with a shotgun. As evidence is examined and witnesses within the house are questioned, Holmes uncovers holes in testimonies and a connection to a secret society that no one wishes to discuss.