Because of spoilers, more after the jump.
All of this makes "His Last Vow" so disappointing, because it almost feels like a fan-penned episode (which is really bizarre, since the credited writer is co-creator Steven Moffat). The villain is Charles Augustin Magnussen (Lars Mikkelsen, Mads' big brother), the "Napoleon of blackmail" who holds sensitive information on a vast number of powerful figures, essentially making him one of the most powerful people in the world. Sherlock discovers that Mary is actually a highly-trained professional killer, who's after Magnussen because of what he knows about her. Sherlock exposes Mary's secret to John, then decides to take Mary's revenge on Magnussen himself.
If that sounds scattered and, frankly, ridiculous, that's because it is. The episode never really finds a structure that works, and more often than not it feels like a Frankenstein's monster patched together from various ideas and fan-service moments meant for other episodes. Though every Sherlock episode has its narrative detours, "His Last Vow" felt like nothing but detours, with the occasional "oh hey, we need to build a mystery, yeah?" This wasn't shaggy storytelling, this was lazy storytelling; that's a shame, especially considering that it could be some time before we get any fresh episodes of this show.
So let's break down what went wrong here:
- Magnussen never felt like a threat. This isn't a knock against Mikkelsen, who did the best he could with what he had. The problem is that, face-licking aside, Magnussen just felt like a guy who was good at manipulation, and the show's attempts to make him "scary" made him seem like a low-rent James Bond villain more than anything else. To that same end, it never really felt like there were any real stakes to his plot. Sure, he had information on Mary that would also hurt John and Sherlock, but there wasn't a palpable feeling that it would happen. His threats seemed empty because he said there would be trouble; there was never anything to indicate that he could back them up. Sure, there's probably something to be said about how the of possibility of evidence for personal ruin is more effective than actually having said evidence, but if that's the point the show was going for, it did an exceptionally poor job of making that clear.
- Mary's reveal felt incredibly forced and desperate. Anyone who's consumed any television drama from the past 15 years (or ever, really) knows that certain characters are marked to be suspicious. Mary was in "The Empty Hearse," when Sherlock's word-cloud-thing prominently produced the word "liar" in relation to her. This show has done fine work in character reveals in the past, using clues that, in retrospect, completely made sense and seemed planted for this very purpose. Sherlock's deduction of Mary being a trained killer, though, mostly came from his discovery of her pointing a gun at Magnussen's head, then shooting him, with the "connecting pieces" seemingly pulled at random from the season's previous episodes because hey, why not? It also just doesn't seem to be consistent with what we've already known about Mary; more than anything else, it felt like a major "twist" that was included because for whatever reason, everyone in John's life has to be some kind of sociopathic personality. Which brings me to…
- The "Sherlock problem" was almost unbearable here. One of the most prominent criticisms leveled against Sherlock is that Sherlock is made the focus of everyone's lives, to the point that the show's other characters don't seem to have an existence separate from their relationships with Sherlock. I admit, this has been a problem in the past, but one that I've mostly forgiven because 1) so much else was working splendidly, and 2) season three seemed more intent on exploring these relationships, particularly John's, so it made a certain amount of sense that so much focus would be put on Sherlock in conversations with other characters. However, in this episode, John and Mary are in 221b Baker Street to have the knock-down, drag-out fight that they need to have now that he knows her secret, only to have the conversation hijacked by Sherlock's monologue about how John's attracted to danger, leading the conversation to once again become about Sherlock. The only other time Mary and John are alone together to discuss this situation, John simply forgives her, effectively allowing the show to sweep their relationship problems under the rug so it can get back to Sherlock's shenanigans. This is so remarkably frustrating and disappointing because for a season that had spent so much time on character development in the first two episodes, "His Last Vow" essentially threw it all away as if to say none of this matters when Sherlock is just so damn cool. It robs the episode - and the season as a whole - of any emotional power that it had built up. (This is true of Sherlock and Watson's "heartfelt goodbye" at the end of the episode, too: a moment that could have redeemed the episode a little, only to have it subverted for more hero worship)
- The episode was spinning too many plates. As I mentioned above, "His Last Vow" felt like a patchwork quilt of things the show wanted to do but couldn't figure out how to coherently make them work. The opening sequence was a terrific showcase for Martin Freeman, as John heads into a drug den to find a missing neighbor, but it never ties into the rest of the episode. For that matter, Sherlock's presence in that same den, and the concerns that he may be using again, appear and disappear within a ten-minute frame, as if to remind us that Sherlock was an addict once, and wouldn't it be interesting if he relapsed, but there wasn't enough time to dedicate to that story. Add to that the Magnussen issue, Mary's reveal, a brief thing about Sherlock having a girlfriend (again, it went nowhere), a major mind-castle set piece, Mycroft being Mycroft, and the tease that Moriarty could be returning next time, and "His Last Vow" never coalesced into a cohesive narrative.
It's a shame that this episode had so much going wrong for it, because along with Freeman's great work in the opening sequence, this was quite possibly one of Benedict Cumberbatch's quietest and well-played episodes. There was a lot of potential here, but ultimately the episode tried to be too many different parts at once, resulting in the whole being an overcooked, disappointing mess. For a season that was doing some interesting, promising things, it's too bad the show couldn't stick the landing.
For those curious, since I didn't put grades in my previous reviews, they would be as follows:
"The Empty Hearse": B+
"The Sign of Three": A-
"His Last Vow": C-
Season grade: B (curved, obviously)