Sherlock: His Last Vow

"I'm a doctor. I know how to sprain people."

After two episodes which play with structure we get something resembling a more traditional plot, although it is not so much a whodunit as a question of precisely how Sherlock will bring down the nefarious Charles Augustus Magnusssen. There's a big twist, certainly, in the revelation that Magnussen's "documents" are stored only in his head, but the structure of this episode is less traditional than it appears.

The unusually prominent political subtext is something new, too. Magnussen is a fairly transparent analogue for Rupert Murdoch, of whom I, as a Guardian reader who has been following the whole phone hacking saga since long before it was fashionable to do so, am most certainly not a fan. I find the description of red top tabloids' activities as blackmail quite apt. It's also nice to see Sherlock shooting the bounder at the end. As he says, "The personal freedom of anyone you've ever met is a fantasy."

But none of this is really the point: this episode is about Mary, whom Magnussen is blackmailing on account of her apparently quite bloodstained past, and the strain which this revelation places on her relationship with John. John's fury, their awkward estrangement over Christmas, and their deeply moving reconciliation are all beautifully written and acted. As per the original Charles Augustus Milverton, however, Sherlock gives not a jot about why she is being blackmailed.

Lars Mikkelsen is splendidly slimy as Magnussen, with a clear undercurrent of sexual molestation in his treatment of both Lady Smallwood and John. But it is, as ever, the small character beats that make this episode shine, from Molly slapping Sherlock for lapsing back into his Class A habit to every scene between John and Mary. Sherlock's explanation to John that he has pretended to be in love with Janine, even to the point of engagement, just to get at her boss, reminds us what a sociopath he is, but it's nice to see she gets her revenge by selling kiss-and-tell stories to the tabloids, which ties in nicely with the episode's themes.

The scenes inside Sherlock's head, after Mary shoots him, are an act of directorial genius, the highlight being Moriarty in his padded shell, doubling as a nice bit of foreshadowing. Appropriately, it is one Louis Moffat who plays the young Sherlock.

Obviously, the highlight of the whole episode is Sherlock and Mycroft being caught smoking by their mother, especially in the light of Magnussen's description of Mycroft as the most powerful man in the country. But the climactic scene highlights the parallels between Sherlock and Magnussen: both are sociopaths, both have "mind palaces", but the parallels end there. 

It looks as though Magnussen has one, but Sherlock manages to cut the Gordian Knot by killing him. It looks as though he faces exile and certain death for this murder, but then we get our cliffhanger: Moriarty is back...