Despite never having read this one before, I called it soon enough.
Second part, as is par for course with Holmes novels MO, was a narration of the history (on a far place and piquant circumstances for the edifice of London society), spawning the issues at present. Was mislead nicely for a bit, but called too by the letter.
I have to say though that both instances were very gratifying conclusions.
The epilogue was an interesting partner to the third chapter in a way.