Here's what we know about the upcoming third season of BBC1's Sherlock based upon this frustratingly short teaser trailer: Mrs. Hudson washes dishes in insufficient lighting conditions, Detective Inspector Lestrade can't find something in his jacket pocket, Mycroft Holmes reads with predictably good posture, somebody who might be Molly Hooper gets something out of a closet, John Watson has a mustache and drinks some wine, Sherlock Holmes walks into a restaurant, and the story will "be continued."
That's pretty much it. Not even an air date. It can maybe be extrapolated that Benedict Cumberbatch and Martin Freeman's Holmes and Watson are in the same restaurant and will eat a meal together, but one should be careful not to jump to too many conclusions in these things, especially considering the lengths of misdirection to which the show went in Season 2's final moments. However, what the teaser lacks in useful information, it more than makes up in simply being definitive proof that Season 3 is coming. Eventually.