Trailer: BBC1's SHERLOCK - Christmas Special

The BBC have released the full-length trailer for this year's SHERLOCK special at Christmas. In an unusual move, the entire episode will transplant Sherlock (Benedict Cumberbatch) and Watson (Martin Freeman) to 19th-century London, apparently with no rhyme-or-reason. Just go with it, OK? Anyway, this looks fun, but there's no real insight into what the storyline is. The trailer just exists to make people double-take that the 'modern Sherlock update' has undone its own concept, to become just another iteration of a Victorian-era Sherlock Holmes. Does that sound too cynical? I don't mean it to be. It'll be amusing to see Cumberbatch and Freeman in more traditional roles, and the Victoriana will be like a warm blanket on a hopefully chilly Christmas evening. What do YOU think? Excited by this special, or a little nonplussed?