This imaginative and mostly delicious hors d'oeuvre for the forthcoming Series IV of the popular and critically acclaimed Brit TV series Sherlock starring Benedict Cumberbatch and Martin Freeman (expected airdate, early 2017) was written by series co-creators Steven Moffat and Mark Gatiss and aired last night on PBS. It finds our heroes spending most of their time in the late 19th century rather than the 21st. We'll not reveal any more about it except to say it was a most unexpected, unusual and welcome treat and, for the most part, a genuinely delightful way to spend an hour-and-a-half glued to the TV screen. A trailer for the episode (one of several) can be viewed here. If you missed the premiere showing, PBS will re-air the full episode 10 January at 10:00 PM Eastern and make it available for streaming for a limited time thereafter.