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"Without giving anything away, this is about as tough a journey as he goes on. Sherlock and John both, actually. This is about as difficult as it gets for them. They kind of go to hell and back this time."
Sherlock co-creator Steven Moffat wasn't bluffing when he told us that the great detective and his partner-in-solving-crime would "go to hell and back" this series.
Both men appear to be reeling in the wake of Mary's death, but while John is truly lost, Sherlock's own 'disintregration' is extremely purposeful. He tears himself down as a way of building John back up – the central twist in an episode that delights in pulling the rug out from under the viewer again and again and again.
For all the skin-crawling moments delivered courtesy of Toby Jones as the hideous Culverton Smith – and they are plentiful – what arrived on BBC One billed as the darkest Sherlock episode yet ("with some scenes you may find upsetting") is secretly a rather uplifting tale of how the rift between two friends is healed.
We should've seen it coming, really – and not just because this episode is called 'The Lying Detective'.
John may be bitter and resentful in the early-going, but the turning point arrives when a cocky Smith invites him and Sherlock to the wing of a hospital he built, and later his "favourite room" – the mortuary.
There's a moment, as the over-confident villain boasts of his power, his influence, his wealth, and how it protects him from prosecution, that John steps in to warn him that "no-one's untouchable" and Sherlock lets slip a little smirk.
John's head is back in the game – and it's telling that the spectre of Mary – who'd been poking and provoking her husband into acting like the man he wants to be is absent whenever the adrenaline's flowing and he's throwing himself into the caper.
'The Lying Detective' is an unusual sort of mystery – anyone wishing that the show would consist of "Sherlock and John solving a case, larks ensue" will doubtless come away disappointed. But it is a mystery nonetheless, playing with our expectations as to exactly what sort of story Moffat is telling until the final act.
Is this the tale of a seemingly unassailable adversary and the terrifying lengths to which our heroes will go to stop him? Or is it the story of how a drug-ravaged Sherlock got it wrong? Might Culverton Smith be an innocent man, albeit a intensely creepy one?
It's a credit to Moffat, and to the stellar performances of uniformly superb cast, that every possibility seems a credible one. We're taken in by every turn, every twist, on this rather dizzying ride.
The whole thing's directed with an impressive flair by Nick Hurran – some of the visual flourishes, like an almost liquid 221b encompassing Sherlock, are spectacular even by the show's own showy standards, and certainly the leap in quality from 'The Six Thatchers' is marked.
It's perhaps only in the final moments of 'The Lying Detective' that Moffat overplays his hand. After so much misdirection, it's hugely satisfying for the episode to end with an emotionally frank exchange between John and Sherlock and the pair striding out of the flat, off into an uncertain future would've been a fitting end.
Instead, Moffat can't resist one last rug-pull – and, much like the nature of Mary's demise last week, the reveal of Euros Holmes feels like a rather cartoonish moment that belongs in a lesser show.
Sian Brooke does a terrific job of disguising herself throughout – sweet, endearing and totally unsuspicious as the fake Faith, mild-mannered and perfectly anonymous as John's therapist. If it weren't for that slightly dodgy wig she wore as John's fancy-woman, fans might never have suspected there was more to 'E' at all.
But ultimately you can't end your story with a villain whipping off their disguise without inviting unflattering comparisons to Scooby Doo. One twist too many perhaps, and certainly the least effective in what's otherwise a smart, scary and brilliant bit of drama.
Our thoughts and questions:
- So was Moriarty's 'return' all a trick orchestrated by Euros? Sherlock did warn John that there was an "East Wind coming" just moments before the "Miss Me?" reveal in 'His Last Vow'.
- So if Euros is the secret Holmes sister, then who or what is Sherrinford?
- Mycroft going for a drink with Lady Smallwood? Mystrade shippers will be fuming.
- Sherlock saw Redbeard again during his drug-fuelled freak-out on the Southbank. Do we know know the full extent of what happened with that dog?
- "You cock. Utter, utter cock."
- So given that he faked his big meltdown to have John come to his rescue, was Sherlock really in as bad a state as we thought? Molly's declaration that he had "weeks" to live seems melodramatic in retrospect - unless, as with his faked demise, she was once again in on the whole thing?
- For all the dark overtones of this episode, there's still plenty of laughs: most courtesy of Una Stubbs, on absolute fire as Mrs Hudson this week.
- "It's gone downhill a bit, hasn't it?" - top-quality trolling from Moffat there.
