For its upcoming Christmas special, Sherlock will be traveling back to the time period in which it was written, and fans can get their first glimpse in the delightfully tongue-in-cheek teaser that was recently released. Watch the clip below, and enjoy everything we've come to love from this series: a sarcastic Sherlock, a blunt Watson, and not-a-plot-device Mrs. Hudson. Oh, and don't forget about Watson's distinguished mustache, which even he isn't all too happy with. And for those of you worried about continuity, don't worry; this episode will exist in a vacuum and won't be connected to the other, modern day episodes.