Sherlock series 4 episode 2: Is Irene Adler coming back? Is HH Holmes a real murderer? Who played Eurus/Euros Holmes? Where has she been? Questions and discussion of The Lying Detective

1. Is John dead?

The episode ended on one hell of a cliffhanger, with Martin Freeman’s John Watson apparently at the business end of a bullet fired by Sherlock’s newly-revealed sister Euros – but will he live to fight another day?

Well…yes. It seems pretty unlikely that John Watson would get killed off right before the finale, so we’re betting he finds some way out of this one.

2. Who played Euros?

Siân Brooke is the woman behind the newest Holmes sibling (as well as the therapist, the woman on the bus and Culverton Smith’s fake daughter), and you can find out more about the TV and theatre actor here.

3. Where has she been all this time?

Brooke in last week's Sherlock episode

The Holmes family are a little dysfunctional, sure, but it seems a bit extreme even for them to have hidden away their sister somewhere unless they had a very good reason for doing so. Equally, it seems strange for her to have been away for so long without ever being mentioned. So why has Euros been absent all this time? And why is she such a secret?

One answer could come from Sherlock series three, when Mycroft (Mark Gatiss) asked “don't you remember what happened to the other one?”, implying through context that their sibling went off the rails in some way.

Meanwhile, in this week's episode he seemed worried that his brother would become a "security risk" just like another family member once had been – so based on this it seems likely that Euros ended up using her intellect for some nefarious purposes that forced Mycroft to put her away. She certainly seems less-than-stable considering she's apparently murdered a therapist and shot at John (plus the whole fancy dress thing).

Less clear is why she's such a secret – even to one of her brothers, apparently.

4. Why didn't Sherlock recognise her?

Sherlock is apparently aware of his secret sister, yet in tonight's episode he doesn't seem to clock that he's spending an entire evening with her while she's disguised as someone else. But why?

Well, there's one answer staring us in the face kids – drug abuse. Sherlock later believes he was so high he hallucinated her entirely, so it's not so out of the question that he might have been too far gone to recognise someone he hadn't seen for years (if not decades).

Then again, he was sober enough to perform advanced observational deductions, so it is still a bit weird. Maybe it's been a very long time since they last saw each other...

5. Why is Euros back now?

Perhaps the third Holmes sibling just broke out of somewhere, or is only now realising some master plan that has been years in the making. Otherwise, we're not sure why exactly she's waited so long to return to her brothers – she could at least have popped in over Christmas.

6. Wait, which one was Culverton Smith’s real daughter and at what point?

Yes, we were a little confused by this one as well, but we think we’ve worked it out. The conclusion of the episode reveals that the woman who came to seek Sherlock’s aid to take down serial killer Culverton Smith wasn’t actually his daughter Faith (as she claimed), but was instead Sherlock’s sister Euros in disguise.

And if you look back at the early scenes of Faith, she is indeed played by a different actress, the same one who returns later in the episode to meet her father (the hair is a dead giveaway). So THAT makes sense – Faith is only impersonated by Euros in the scenes with Sherlock.

The bit that we’re still a little confused about is how exactly Euros got her hands on the evidence the REAL Faith wrote (she says she got it from Culverton Smith via a mutual friend, who we sort of thought might be Moriarty, but how did that work?), or how she even knew about it, or even why Culverton kept the incriminating paper around… but hey, we’re sure that’ll be explained next week.

Or they’ll just distract us with another car chase, that works too.

7. Will Mary be in next week’s episode?

Amanda Abbington’s Mary Watson made a surprise return in The Lying Detective, appearing to her husband John after her death in last week’s episode as a manifestation of his subconscious.

Of course, this leaves the door open for Abbington to reprise the role again in future episodes, but given that this week’s story seemed to bring closure to John’s reaction her death we’d be surprised if she continued to be as major a feature going forward.

8. Is Irene Adler returning to Sherlock?

Lara Pulver’s dominatrix/criminal Irene Adler, aka ‘The Woman’ who bested Sherlock in 2012 episode A Scandal in Belgravia, was last seen in the series when she returned for a cameo appearance in 2014’s The Sign of Three (though only in Sherlock’s Mind Palace), so you’d be forgiven for assuming we’d seen the last of the sleuth’s sort-of love interest.

However, tonight’s episode revealed (via raunchy text alert) that Miss Adler and Sherlock are still in contact, inspiring Martin Freeman’s John Watson to insist his friend try and make something of their connection (even if it is just a dirty weekend in High Wycombe). So fingers crossed we haven't seen the last of The Woman in Sherlock.

9. Were HH Holmes and his murder castle real?

Yes – the inspiration for Culverton Smith’s nefarious schemes WAS a real murderer, who killed at least 9 people (but possibly as many as 200) in his World’s Fair hotel in the late 1800s, going down in history as one of the first serial killers in the modern sense of the term. The BBC upholding its commitment to education, there.

10. Who or what is Sherrinford?

So it turns out that while the long-rumoured third Holmes sibling does exist, she's not a man called Sherrinford after all, calling into question who or what the ‘Sherrinford’ is that Mycroft called in last week’s episode (and had an appointment to call in tonight’s).

Could it be that Sherrinford is a code name for his sister Euros, or perhaps refers to some sort of facility where she was kept, hence why he described it as “secure”? Or is Sherrinford something completely unrelated – a person or organisation who Mycroft is monitoring that has nothing to do with the Holmes family?

We go into the origins of Sherrinford in a bit more detail here, but one thing seems certain – it looks like anything involving Tom Hiddleston is out. Sorry guys.

11. Did Mrs Hudson really drive that car?

Una Stubbs is a performer of many talents, but stunt driving isn’t one of them – instead, a James Bond stunt performer took the wheel for her Aston Martin chase scenes.

12. Will Mycroft date Lady Smallwood?

One of The Lying Detective’s lighter moments saw Lady Smallwood (Lindsay Duncan) make a bit of a pass at Mark Gatiss’s Mycroft Holmes, giving him her number and asking him for a drink.

We’re not quite sure how this new romance will play out – we can’t imagine Mycroft being the easiest person to date (or that dating is something he even does) – but hey, with the might of the British government behind them they’re definitely a power couple. And he did go back and pick up her business card so he must have some interest in her...

13. Is next week the last episode of Sherlock?

It’s called The Final Problem. Things are more dangerous for John and Sherlock than they’ve ever been before. And series creators Steven Moffat and Mark Gatiss have been giving mixed responses as to whether they’ll be able to continue the series going forward.

So there’s a chance, yes. But all involved have also said never say ever, so we choose to hope we have much more to see of Mr Holmes after next week, and no-one can take that away from us.

(Well, at least until there’s an official announcement or something).

Sherlock continues on BBC1 next Sunday (15th January) at 9:00pm