The Valley of Fear (Unabridged) [Unabridged Fiction‪]‬

An English gentleman is murdered with a uniquely American weapon: a sawed-off shotgun. Since the police are baffled, Sherlock Holmes is asked to solve the murder.

The story is similar in structure to "A Study in Scarlet", with the second half taking place in the United States and filling in the history of what led up to the first half. Toward the end, the story comes back to Holmes and Watson.