Curse of the Baskervilles
In three more adventures, the intrepid duo tackle a ghostly locomotive, journey to Dartmoor in search of a gigantic hound, and team up with bloodthirsty psychiatrist Hannibal Lecter in the hunt for a murderer. Adult humour throughout.
Curse of the Baskervilles is book #3 in this Victorian comedy adventure series.
If you love historical mysteries, buy something else instead, but if you're into fart-gags and innuendo this'll be right up your Victorian street.