Reviewed by David Selby

I can only echo the views expressed in last week’s spoiler-free review. His Last Vow was an engaging, sinister and jaw-dropping series of affairs that brought a worthy but unexpected close to what was perhaps the best series of Sherlock yet.

Whilst the viewing reception has been undoubtedly stunning (I’ve never heard more discussion about a TV show), the critical reactions to the episodes have been generally mixed. This is only to be expected considering that the series has evolved into something which is driven by characterisation rather than case. Indeed, His Last Vow was characterisation at its finest. Sherlock’s humanity has reached its pinnacle – he has finally been exposed. He has a number of weaknesses; his cold-heartedness is a visage, and John’s influence, as shown in the previous episode, has changed him. He’s still a high-functioning sociopath and a floor-wiping genius but he has depth. The most touching scene in the episode for me was the revelation of Redbeard. It was easy to shed a tear for Sherlock, who has never connected with humans but is reunited with the one creature he felt affection for – the one thing that calms him. It’s heart-breaking to see him drawing a comparison between the pet and himself. Sherlock is finally a relatable human being.

Mary’s revelation meanwhile could have been predicted, yet it was surprisingly unforeseen when it came in the episode. Initially the idea alarmed me, but the use of the singular word ‘Liar’ seemed to epitomise the issue ingeniously. Mary is a complex and dark yet still somehow likable character and has thus grown to become one of my favourites.

Magnussen was a perfectly repulsive antagonist, defined entirely by his lack of respect towards others. I don’t think I’d be unreasonable to say that I prefer him to Moriarty; he’s subtle and manipulative yet completely abhorrent. In spite of the criticisms, Sherlock’s decision to ‘murder’ him had foundation. The episode was about the mind and it was pivotal that Magnussen was stopped. The episode’s almost dizzying cinematography suited the mood and direction. It has become on one of Sherlock’s defining characteristics.

If I were to fault the episode, I would say that Sherlock’s attitude towards Janine is unnecessary. The two made quite a couple in The Sign of Three, and it was a shame to see their chemistry undermined for the sake of the case. As she may be a returning character, however, they could yet surprise me. There’s also the case of Moriarty being back from the dead. I’m loathed to criticise it at a stage when it could go in any direction. So, instead of voicing my concerns that it will ruin the Series Two finale, here are a selection of my theories for the resolution:

Theory A

Quite simply – and if used, disappointingly – Moriarty survived the fall, like Sherlock, by faking his death by using a fake gun and ‘window dressing’. He’s now back in a Reichenbach-esque scenario to cause even more trouble as Sherlock’s recurring nemesis.

Theory B

Moriarty somehow survived but has now gained access to the seemingly impossible ‘door-opening’ computer code spoken about in the Series Two finale. Now, he’s a menace to the whole world and is planning something on a devastating scale – even going as far as destroying the planet.

Theory C

Moriarty survived in a Phineas Gage-esque scenario where he intended to kill himself but instead returned with brain damage as a completely new man. He’s still an underlying villain, but has different motives and a darker, more brooding personality. This would be my preferred set-up.

Theory D

Moriarty is, in fact, the lost brother of Sherlock and Mycroft. There’s been a lot of focus on their family life and Mycroft casually mentioned ‘the other brother’. He could be referring to Sherlock or perhaps another who was given away at birth. It would explain his fascination with Sherlock but also his vengeful desires and storybook complex which ran throughout his previous arc.

Theory E

It is Moriarty – but it’s not James Moriarty. Because, of course, Jim had an identical twin.

Theory F

Moriarty and Sherlock conspired together for a currently unknown reason and faked both of their deaths to build up to something bigger.

Theory G

Someone else is behind it all.

One possibility is that his ‘return’ was a ploy to get Sherlock back into the country arranged by the likes of Mycroft. Another is that, like Sherlock, Moriarty has his own fan-club. From the unconvincing mouth movements, a mere animation seems likely.

Maybe we never even saw Moriarty – maybe Andrew Scott played innocent Richard Brook the whole time.

It could be a follow-up arranged by Moriarty prior to his suicide using recorded footage handed down to his ‘successor’. Or perhaps Moriarty had nothing to do with it and it’s someone else who wishes to use a façade. But who?

Episode Verdict: 9.5/10