The Hound of the Baskervilles (1914)

In this early version the classic "Hound of the Baskervilles" mystery is not faithfully adapted, Watson's character is absent and there are two Holmes. Holmes' foe is called Stapleton and he menaces Holmes' client Lord Henry and his fiancée, Laura Lyons, masquerading himself as Holmes. Hidden passages, hand bombs and mechanical devices abound, reminding more of a serial than of a Conan Doyle story.

Unfortunately the movie The Hound of the Baskervilles is not yet available on HBO Max.