Reviewed by Louis Rabinowitz.

“It’s not a game anymore.”

The tagline for Sherlock season 4, blaring from the trailers pasted wall to wall on the BBC, neatly summed up what this season, subject to endless speculation about whether it’ll mark the show’s end, is aiming to do. It promises something darker, with real and tangible consequences – but most importantly, it promises something entirely different, even opposite, from what we’ve seen before.

It’s not a surprise, then, that The Six Thatchers offers us an entirely different vision of Sherlock. It’s flashier, bigger in scope, and its central plotline draws straight from the Bond or Bourne playbook in its story of espionage and sabotage. There’s not a single mention of the ‘mind palace’ conceit that dominated the second and third seasons, and the only detective mystery is solved within the first half hour. Most curiously, the show’s co-lead character barely factors into the storyline. Suffice to say, we’re a long way from the days of Sherlock and John Watson solving mysteries out of Baker Street.

But is that a good thing?

The answer, kind of predictably, is somewhere in between yes and no. The Six Thatchers is a conundrum of an episode – not in the traditional Sherlock sense where the haziness is intentional, and where complete clarity about the episode’s plot is offered by the final act. Instead, it’s as if you can see Mark Gatiss, the episode’s writer (you can blame Moffat next week, I promise) struggling throughout to figure out what The Six Thatchers is actually about. Inevitably, that identity crisis means that the episode is a messy one, filled with non sequiturs and gratuitous winks to fans or to canon. Yet, lurking beneath that mess is a really interesting episode that genuinely delivers on the promise of that aforementioned tagline, delving into darker and more challenging themes than Sherlock has yet explored before ending with a huge change in the status quo that can’t handily be waved away like many previous twists on the show. The Six Thatchers aims for a high target, and falls a little short – but its ambition is absolutely commendable, and there’s a lot of potential for the subsequent two episodes to channel that ambition into a slightly less bloated narrative.

Unusually, the central character here was Mary, as The Six Thatchers delved into the loose ends posed by His Last Vow’s reveal of her true nature. Her story is the spine of the narrative, essentially serving as a literal version of the Appointment in Samarra proverb that keeps cropping up as Mary faces the consequences of a job that was always meant to be short term, no matter how much effort she puts into evading those consequences. And there’s a lot of really interesting character material for Mary here that sheds clarity on her overarching journey as Mary Watson in a way that maintains her own agency as a character. As frustrating as her death is in many ways, given the vanishing amount of women that play an important role in Sherlock’s narrative (Molly and Ms Hudson, for instance, have negligible impact on the story here), it hits the right notes as an inevitable consequence of the lifestyle she chose. Her death is certainly predictable, but in a calculated way – it’s the only way her story could realistically end, both in terms of her cutthroat profession as an assassin and in terms of the books’ canon, in which her death is as tied up with her character as Gwen Stacy in the Spider-Man comics. What matters is that the moment itself hits as an emotional gutpunch, and it does. Amanda Abbington does sterling work throughout, both with the tough grittiness of an assassin and the rawer vulnerability that she exhibits in her death scene, ensuring that her final appearance (barring flashbacks) is a reminder of how quickly she made herself a valuable part of Sherlock and created believable and nuanced relationships with Freeeman and Cumberbatch.

The other major through-line of the episode belongs to Sherlock’s own journey of realisation, where he finally learns the consequences of his unchecked arrogance in the harshest way possible. This isn’t really as clear as Mary’s storyline because there’s not a lot of foreshadowing for that final moment where Sherlock proves just how blind he is to his own behaviour by goading Norbury into taking a shot at him. It’s something, like the ideas of fate and predestination that Mycroft brings up in his scenes, that The Six Thatchers is only periodically committed to as it continues to spin unnecessary plates, losing sight of the stories it’s meant to be telling at points. Yet the moment where Sherlock’s actions instantly backfire is such an interesting one that the muddled journey seems almost forgivable. It’s a deliberate subversion of the comprehensive deductions that are always presented as comic or impressive – one that’s done out of petty, unnecessary spite, and exists to prove Sherlock’s naïve belief that he has total control over his surroundings.

Benedict Cumberbatch dials up the manic intensity of detective Sherlock to eleven in his final scene with Norbury, but his most interesting work comes after, which is far quieter and more understated than his usual emotional theatrics, powerfully illustrating how stunned and ashamed Sherlock feels after Mary’s death. Sherlock, in many ways, is a character who exists to stay roughly the same. Granted, he’s been humanised by his relationship with John, developed into a more approachable character than the person we first met. Still, such a major realisation is a big statement of intent, the kind of shake-up to the nuts and bolts of Sherlock that this purportedly dark and consequential season really needed. A lot depends on whether the following episodes keep up with this changed characterisation or eventually revert back to Sherlock the insensitive genius unchanged, but it’s a promising sign of the kind of major character development that Sherlock has often shied away from in the past.

With all that said, these two storylines, despite how bold and interesting they can be, don’t exist in a vacuum, and the stuff they share space with is pretty uneven, often dragging down the emotional impact of a solid character moment or a thoughtful piece of dialogue. The easiest culprit is John Watson. As a lot of people have pointed out, Watson is as important to Sherlock as Sherlock himself is. He’s the Greek chorus, the everyman who interprets the action for us as viewers, and his role means there’s always someone to easily empathise with when Sherlock becomes particularly distanced from us. It’s true that Watson’s begun to share this role with others more as the show’s ensemble has broadened out, but his function as the other half of the coin is still vital. It’s strange, then, that he’s so tangential to any of The Six Thatchers’ major storylines, despite how much of the episode centres around Mary and her new life with him. Most of the time, he either tags along and snatches a few spare lines of dialogue that could have been given to others. At one point, he is literally replaced by a balloon, which changes nothing. He then arrives late to his wife’s own death, missing out on the events that would actually provide full justification for his furious reaction at Sherlock.

The one attempt to give him a role in the story results in The Six Thatchers’ biggest mess, which is his strange text affair with the unnamed bus woman. The storyline opens up a can of worms about John’s character that Sherlock is entirely unwilling to tackle – it’s far too fraught with complications and impactful on John’s actual likeability to serve as the meaningful side note that the episode wants it to be. Furthermore, there’s no real purpose for the story in the wider narrative – it doesn’t easily link up with Mary or Sherlock’s stories, and Mary dies before the secret can be revealed, so it just serves as a narrative cul-de-sac that drags attention away from the A-plot just as events begin to ramp up. Not every episode of Sherlock needs to have a big role for Watson, but the nature of The Six Thatchers means that his minimal role in events diminishes the episode as a whole, and that clumsiness (most of Mary’s big dramatic scenes are primarily with Sherlock, and their relationship isn’t particularly important to either of their stories) is only exacerbated by the poor attempts to give John some screen-time. It’s a textbook example of Sherlock getting in its own way, and it creates a frustrating amount of missed opportunities for interesting drama between Mary and John.

While Mary’s story is a strong one as a whole, some of the nitty-gritty is equally clumsy in its writing. Ajay, the surviving AGRA member for instance, is set up as a pivotal character – an incarnation of the consequences of Mary’s old life that provides most of the episode’s immediate peril in his Terminator-like attempts to track down and end his target. He’s even given a reasonable amount of back-story complete with flashbacks to justify his monomania, thereby complicating Mary’s character and initially dividing our loyalties as viewers by exploiting the murkiness of her past as a freelance assassin. Yet his feud with Mary ends up dramatically inert, because Ajay is entirely wrong about her role in events, with his furious quest to track her down based on a bit of hearsay that he misinterpreted. It’s an opportunity to challenge Mary’s morality, and hammer home that theme of actions having inevitable consequences that’s passed up with a hand-wave that Mary did nothing wrong – she’s facing consequences for someone else’s actions, a conflict that just isn’t that interesting. The Six Thatchers eventually refocuses on a more interesting antagonist, Norbury, who’s a subversion of everything you’d expect from an evil mastermind yet ends up doing more tangible damage than any previous foe, who does pose an interesting conflict for Mary. Yet it’s hard not to feel like all the time spent with Ajay was a little wasted given his inconsequential role in Mary’s character arc – another cul-de-sac that ends up with just a few inches of progress in the story, yet takes up huge amounts of screen-time.

At the end of the day, The Six Thatchers delivers on the promise of consequences. By the end credits, Mary’s dead, and John has completely cut Sherlock off – a complete destruction of their relationship that’ll take far longer than a gap between episodes to repair. Both of those twists have an emotional wallop, and the intense start to the season bodes well for the following episodes to pack their own punch, so everything is in place for a fascinating season to come. Yet the journey to those twists is a roundabout one, bloated with unnecessary detours and uncertain of its own tone as the episode shifts from light character-based comedy to tragic life and death, and it’s not entirely clear whether the ends justified the means here, given how messy and contradictory the end product is. At the very least, this was a fascinating experiment of an episode, and if it didn’t all come off, then the moments that did land, and the intent that’s evident throughout, is a compelling reason to keep faith in Sherlock, and a sign that this is still a show capable of things that the rest of television simply can’t match.

Rating: 7/10

The Six Thatchers shows Sherlock struggling to learn the lessons of its past and apply them to keep moving forward into the future. It’s an uneven episode that’s often inspired but often ambling and unfocused; one that certainly won’t go down with the greats of previous seasons, but deserves a spot as an episode that refuses to rest on its laurels and keeps trying to pursue new stories.

Next up, then, we have our customary Sherlock vs despicable, powerful villain episode, with an added slice of Sherlock and John angst as they struggle to repair their relationship. The villain in question is Culverton Smith, who you might have seen smiling out from a bus shelter poster here. From the looks of the trailers, he is not a nice man.