While there is more than a year to wait for the episode, Steven Moffat has let fans in on a little secret. That secret is that for Christmas 2015, there will be a holiday themed episode of Sherlock. While that alone is exciting news, he gave fans even more insight when he announced it would be a true telling of the short, The Adventure of the Blue Carbuncle, by Sir Arthur Conan Doyle.
In the story, a Christmas goose is used to pull off a very elaborate robbery. When the goose ends up in the hands of Sherlock, he and Watson begin to explore just what happened. While there have been several film adaptations produced over the years, it will be interesting to see the unique storytelling that the writing staff on Sherlock typically employ. Be sure to catch the holiday themed episode when it airs December 2015.