Sherlock Holmes: The Adventure of the Antiquarian's Niece

A Sherlock Holmes novelette of 10,000 words, set in the universe of H.P. Lovecraft's Cthulhu mythos, narrated by Dr. Watson. Holmes and Watson start out investigating the mysterious behavior of the inhabitants of the sinister Depewatch Priory - and then find themselves up against forces more monstrous than they'd originally bargained for.