Miss me?

Yes, another blast from Sherlock’s past returned in Sunday night’s episode, in a huge twist that added a major new character to the original Sherlock Holmes canon, confounded fans who had been expecting to be introduced to a third Holmes brother, yet had nothing to do with arch-villain Moriarty (as far as we know).

Sherlock and Mycroft have a sister, and she’s been hiding in plain sight for the last two episodes.

As The Lying Detective came to an end, John’s therapist divested herself of her Germanic accent and her glasses, revealing herself to be none other than the woman he had been involved with in an elicit sexting relationship after meeting her on a bus in episode one. 

At the same time, Sherlock found the piece of paper supposedly given to him by Faith, the daughter of this week’s villain Culverton Smith, and spotted a secret message on it – Miss Me? 

That proved that his apparent drug-addled hallucinations of a night spent with her were in fact real – but that she had not been Smith’s daughter, and was instead Sherlock’s own sister, whose name she revealed to John is Euros (or Eurus), admitting "my parents loved silly names".

Sherlock creators Mark Gatiss ad Steven Moffat have played fast and loose with certain aspects of the Sherlock Holmes canon in the past but they’ve gone further here, introducing us to a whole new member of the Holmes family never even hinted at in the original books, and putting paid to the idea that “the other one” Mycroft mentioned at the end of series three was a third brother (or that he would be called Sherrinford or that he would be played by Tom Hiddleston).

They have however paid grand tribute to Sir Arthur Conan Doyle’s Sherlock Holmes by making Euros a master of disguise, just like the hero of the books. Although Benedict Cumberbatch’s detective has briefly taken on other guises during the series, having him fully transform himself was unlikely to have ever fooled fans. So giving that talent to a character we hadn’t previously met was a stroke of genius, and one that seems to have paid off (there must have been a couple of hundred people at the screening of the episode on Sunday and, of those, only two raised their hands when asked if they had guessed the twist). 

Of course, Euros’s different personas were made all the more convincing by her talent for accents, and for that – and for the performances in general – credit has to go to actor Sian Brooke.

As a reminder, in episode one she added a red wig, a Scottish accent and a coquettish manner to become ‘E’, the woman John almost-but-not-quite had an affair with…

In episode two she turned northern to play Culverton Smith’s daughter Faith, spending an evening getting reacquainted with her drug-addled brother (even though he, with all his supposed powers of observation, had no idea).

And in the same episode, she aged herself 20 years and became John’s German therapist, all without a false nose in sight. Genuinely impressive stuff.

Of course we’re now left with numerous questions about Euros – not least how to spell her name, but also including: Where has she been all this time? What did Mycroft mean when he said “you remember what happened to the other one” in series three? Why is she back now? And, of course – the big one – did she really just shoot John Watson?

If so, it’s safe to say, Sherlock is unlikely to be given to outpourings of brotherly love, even when it comes to his sister…

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