A convicted thief in Dartmoor prison hides the location of stolen Bank of England printing plates inside three music boxes. The boxes are sold at a localauction house. When Dr Watson friend Julian 'Stinky' Emery a avid collector, pays Sherlock Holmes and Dr Watson a visit and tells them a about a strange robbery in his house the previous night, in which someone stole a music box that he had bought at a auction for a measly two pounds. Later that night it is discovered that Stink is Murdered, and Holmes and Watson realize that someone is willing to kill to obtain the three music boxes. When Holmes and Watson go tothe house of the people who bought the second music box, they find it stolen as well. Sherlock Holmes is able to buy the third music box, and ask Scotland Yard to track down the suspects. Later it is found out that the Inspector who had been tracking the suspects has been murdered. Holmes and Watson soon crack the code of the music box and discovered the numbers on the keys correlates to a letter in the alphabet, unfortunately they are only partial able to de code the whole message because the suspects have the other two music boxes. When Holmes he discovers his flat has been ransacked in a attempt to find the third music box, he notice a cigarette with a distinct type of tobacco. Holmes tracks down the lady who bought the tobacco and confronts her. While Holmes is confronting her he is ambushed and tied up and led to a warehouse. Back at Holmes and Watson flat Hilda Courtney steals the music box from Dr. Watson. Holmes escapes from the warehouse nearly escaping death and returns to the flat where Watson tell Holmes that the music box has been stolen. While talking to Holmes, Watson cracks the code for the location of the five pound engraving plate, when he tells Holmes about a quote from Dr. Samual Johnson. Hilda Courtney and her gang decipher the code leading them to go to the house of Dr. Samuel Johnson. While Courtney is stealing the plates Holmes ambushes them and Scotland Yard arrest Courtney and her constituents before they can get away and returns the plates back to the Bank of England.
