'The Boscombe Valley Mystery' is a Sherlock Holmes short story by Sir Arthur Conan Doyle, first published in The Strand Magazine in October 1891. It is the fourth story in the collection The Adventures of Sherlock Holmes. Set in rural Herefordshire, the case involves the murder of a local landowner, Charles McCarthy, and the arrest of his son James, who is seen as the prime suspect. With conflicting witness accounts and hidden tensions, Holmes is called in to uncover the truth behind the crime. The story highlights themes of loyalty, justice, and buried secrets from the past.