Now - one Emmy nomination, two BAFTA wins and countless other awards and plaudits later - the second series premiere, 'A Scandal in Belgravia' picks up mere moments later. And just wait till you see how Steven Moffat - writer on episode one and the show's co-creator - gets our heroes out of this particular fix!
One of the first things that struck this writer upon viewing 'Scandal' for the first time at a recent press event was just how funny it is. That's not to say that it's a 'comedy' episode - far from it. There's some marvellously funny sequences in this first episode, but they're balanced with just the right amount of action.
The action sequences are superbly handled by returning director Paul McGuigan (more on him later), while Moffat continues to exploit Sherlock and John's classic odd-couple relationship to its fullest, with the chemistry between Cumberbatch and Freeman never failing to entertain. Amongst all the action scenes, tense character moments and general derring-do, it's easy to forget just how sharp and witty a show Sherlock was, and indeed continues to be.
Though he's still playing the same man at heart - Sherlock is brilliantly logical, often hilariously blunt - his interactions with Lara Pulver's Irene Adler certainly breathe new life into the character. As for Pulver herself, she's perfectly cast as a modern-day Adler - a different interpretation of the character than Holmes fans may be used to.
While we can't give away specifics, we will say that Pulver brings the charm and sex appeal that the role demands in spades. There's certainly an attraction of sorts between Adler and Sherlock, though it's not nearly as simple as a 'romance'...
And let's not forget John Watson. Sherlock's partner-in-fighting-crime is too often neglected, but Martin Freeman's perfectly judged performance in series one quickly put paid to that. He remains on top form this year - one of this writer's favourite scenes from 'Scandal' doesn't feature Sherlock at all. For a brief scene, Watson takes centre stage and Freeman absolutely shines.
Any preview of 'Scandal' would be incomplete without further discussion of Paul McGuigan's truly excellent work as director. The phrase "visually stunning" is perhaps thrown around a little too often, but McGuigan's work here certainly merits that description.
Certainly, watching episode one on the big screen, there were several moments that took the breath away. Thanks to McGuigan's guiding hand, Sherlock as a show is perfectly suited to contain Sherlock the character - both are effortlessly dynamic, effortlessly cool.
If this preview is in danger of sounding unremittingly positive, that's simply because 'A Scandal in Belgravia' is a fantastic piece of work - Moffat's script, McGuigan's direction and fine performances from the cast all come together to create something really special.
Our sole criticism concerns the episode's final scenes - the resolution to the 'Scandal' case is perhaps a little too far-fetched, even for Mr Sherlock Holmes. But that aside, this is a fantastic piece of television - another Conan Doyle tale has been transposed into the modern day with style and aplomb, and there are enough knowing nods to the great author's original stories to please even the most hardcore Sherlockian.
The return of Sherlock has been a long time coming, but ultimately it's well worth the wait. Now we're desperate to see episode two - Release the Hounds!
Sherlock returns to BBC One on New Year's Day at 8.10pm on BBC One.