The secret to Irene Adler’s success is that she ‘knows what they like’. The fragrant, poised Adler, played by sweet-faced, sly-eyed Lara Pulver, is a dominatrix with a list of influential clients and an understanding of the importance of leverage – in more than just using a whip. Unfortunately, some information burns even the @whiphand that holds it.

Sherlock, who has been impatiently auditioning a series of boring, boring and moderately interesting clients since his last confrontation with Moriarty, is dragged to Buckingham Palace in a sheet. For those interested, Benedict Cumberbatch has very nice feet and even flashes a bit of bottom at one point. Reluctantly intrigued by Adler – who works professionally under the name ‘The Woman’ – he agrees to retrieve pictures of a certain ‘young female person’ who dallied with the dominatrix.

He will, he boasts, have them by the afternoon. It turns out not to be that simple. Adler knows that he is coming, and proceeds to catch the usually poised detective on the wrong foot. She challenges and teases him, always keeping him not entirely sure where he stood with her. Part of it is sex, Adler is a knowing, gleeful sexual predator, but as much is the challenge. Adler isn’t easy for him dissect.

Some clever banter, a bit of whipping and one attack by angry, armed men later – Sherlock is embroiled in a relentless, fast paced plot that frustrates, intrigues and challenges both him and the reader. The secret of writing a mystery is to give the readers enough so they aren’t completely confused, but not enough to solve the crime before the detective. Steven Moffat does a good job with that. I never quite drew ahead of Sherlock, but sometimes I managed to keep up with him and I was usually a bit more on the ball than Watson.

The twist with Adler certainly caught me by surprise, perhaps it wouldn’t have if I wasn’t familiar with the original source material. Arthur Conan Doyle’s ‘Scandal in Bohemia‘ might have been the inspiration for the episode, but this was a very different story to the original. In some ways it improves – there is no denying this was a brilliant, compelling bit of writing – but in others I don’t like what they did to the mythology. More on that later though. First, we’ll talk about what did work.

Although Martin Freeman’s Watson had a few fun moments in this episode – his successful blog and a brief assault on Sherlock that was quite clearly the result of some repressed rage – the meat of it all went to the lovely, dark triptych of the Holmes brothers and Adler and their clever, twisted, almost incestuous games. Adler might not be their kin by blood – a twist too far – but intellectually her mind works in the same way. She shares Sherlock’s pure delight in intellectual puzzles, yet is worldly enough to match wits with Mark Gatiss’ Mycroft. It is a delight to watch Pulver on the screen, there is a glee in her Adler, playing games all the way to the finish line, and her fascination with Sherlock was wholly convincing.

Yet it is the fraternal relationship between the brilliant, weird and damaged Holmes brothers that catches the imagination. The episode was rife with hints about the brothers childhood – ‘There’s a whole childhood in a nutshell,’ Sherlock says caustically of his brother’s offer to ‘be mother’ – and glimpses of the odd but genuine affection between them. Most people might not recognise it as affection, but it is probably as close as either brother can get. It is also interesting to compare how the apparently more socially capable Mycroft is usually alone in scenes, while the always venomous Sherlock is surrounded by people who care. There is a gentle, philosophical moment in a hospital corridor where the brothers contemplate how they don’t work quite right, and caught in profile the two very disparate actors look momentarily, strikingly similar.

Which brings us back to the elements about the show I didn’t like. Taken on its own merits, Moffat’s ‘Scandal in Belgravia’ is a brilliant bit of storytelling and a worthy return to the screen for BBC’s modern day Sherlock. It is when you compare it to the original that problems start to crop up.

Usually I do not object to adaptations taking liberties with the original material. After all, the unaltered story is always going to be available for reference and enjoyment. Narratively, that is what happened here. Moffat has updated Conan Doyle’s tale into some new and interesting. The problem is that the changes are indicative of something rather discomfiting regarding the role of women in the mythology of BBC Sherlock.

Spoilers ahead. Go watch it on iplayer if you want and come back.

Conan Doyle’s Irene Adler was an intelligent, charming and ultimately good woman. She matched wits with Sherlock and came out ahead on her own merits, impressing Sherlock with her morality* and her wit.

In Moffat’s adaptation Adler’s agency was for rent. She was a dominatrix, but she was never in control. Her actions, her interactions, were influenced by a man. I doubt it was Moffat’s intention, but the uncomfortable implication was that, of course, a ‘mere woman’ couldn’t outwit Sherlock. She couldn’t even be the architect of her own salvation, or even her own sexuality. A woman who spent her life controlling her sexuality surrendered it to Sherlock.

It was uncomfortable watching that unfold on the screen. Particularly when you look at the other women in the BBC Sherlock mythology – the revolving door of Watson’s women who he lets Sherlock cheerfully insult? Loo Brealey’s endearing, but increasingly dismaying Molly Hooper, a clever young woman who grovels like a lackey under Sherlock’s abuse? Mrs Hudson is the closest thing to a positive female figure in the mythos, and while I find Una Stubb’s portrayal fun there are still issues with it.

It’s just a shame. I really wanted to enjoy this episode, and I did – it just left a bad taste in my mouth. Unfortunate. Poor Irene Adler, apparently being a strong, capable woman in the Sherlock mythos really gets in the way of story telling for some reason.