The Boscombe Valley Mystery is the fourth of the 12 stories in The Adventures of Sherlock Holmes. It was first published in the Strand Magazine in 1891.
Holmes is summoned to a community in Herefordshire where a local landowner has been murdered outdoors. The deceased's estranged son is strongly implicated. Holmes quickly determines that a mysterious third man may be responsible for the crime, unraveling a thread involving a secret criminal past, thwarted love, and blackmail.