This episode of 'Sherlock' appeared to have half the amount of script of a normal episode, with Moffat and Gatiss opting to divert from their usual high-octane theatrics in favour of something a bit more reflective, self-referential and very, very sentimental.
This was a bizarre episode, with self-confessed "high-functioning sociopath" Holmes on his best man behaviour - which meant using all his crime-solving, nation-protecting powers merely to control the people and permutations around him at the wedding he so clearly abhorred, before paying tribute to his favourite sidekick, via a Conan Doyle-esque recounting of some of their strangest cases.
This combination of montage and memory lane made for an unusual show, somewhere between a Christmas one-off, a Comic Relief-inspired parody and one of these special dream-sequence sitcom episodes.
Finally, the case of the ghost lover brought things just about back on track, some Dr Who gimmicks notwithstanding, with Sherlock calming down long enough to realise the malefactor was very close at hand, and ready to throw something more harmful than confetti into the mix.
Cumberbatch seemed almost too relaxed at times, leaving it to his distinctive timbre to curl around EVERY sentence significantly, doing his best impression of Scar out of the Lion King, even when he was just phoning Mycroft. And that was BEFORE Sherlock and Watson got drunk together, and 'Who Am I?' foundered with Holmes unable to recognise either himself or Madonna. He might have tracked down the ghost lover, and might have shown just what a true friend he really is to both John and Mary Watson, but he's going to have to toughen up if, heaven forbid, a REAL villain comes along...