Without any spoilers, let me say, this is simply the best story on television. Bringing Sherlock Holmes to the 21st century seemed impossible to me, but I completely believe Cumberbatch and Freeman in their roles. Holmes as a dysfunctional geek just seems natural. He reminds me of Sheldon Cooper on the Big Bang Theory. The writing on this episode is riveting, and I didn't want it to end, but when it did it left me soaring. Having read the original material, I believe that Moffat has, in adapting it to this episode, produced a masterpiece that exceeds Conan Doyle. I am pretty jaded when it comes to both literature and the media, and I am not ashamed to admit that I both cried and pumped my fist in the air for this episode. Well done, Mr Moffat, well done!