Just in time for Throwback … Wednesday, the BBC today released the first trailer from the upcoming Sherlock Christmas special set in Victorian times. Just as in the episode’s first clip, the trailer shows off all the wonderful 1800s-y goodness fans were hoping for: gaslights, fog, enormous mustaches — and of course, Holmes’s famous deerstalker cap. (This is the part where we state that such a hat was never mentioned in Conan Doyle’s novels, just to stave off any pedants in the comments.) There’s still no word of a release date; in fact, one might say it’s a mystery.