Summary: Watson brings this case to Sherlock’s attention. An engineer had lost his thumb in a mysterious incident where he’d been asked to fix some hydraulic press thing but was sworn to secrecy. A German woman told him to run away, but he didn’t listen, and then the people tried to kill him and he lost his thumb as he tried to escape. Sherlock took the cops to the place, which had burned down, and the criminals had fled.
Reaction: A gory little mystery. I was entertained.
Sherlock Rating: Started good, but the end…Seriously? An accidental (kind of) fire and then the bad guys get away? So disappointing!
Mystery Story Convention: I would say that the victim being sworn to secrecy by a questionable character appears to be a mystery convention, and there was plenty of that here. As a side note, don’t go around doing jobs for questionable characters who swear you to secrecy, no matter what the pay.