This review will give SPOILERS to the episode “The Six Thatchers.” Please be advised.

2017 is already a better year than 2016 for the simple fact that we have a full series of Sherlock episodes to watch! It’s been a very, very long time since we last had to worry about Sherlock (Benedict Cumberbatch), John Watson (Martin Freeman), and the rest of the Baker Street Gang; two years since series 3, which was all about Sherlock dealing with John’s newfound love with Mary (Amanda Abbington). Read my review of “His Last Vow” to get up to speed on that. And the 2016 New Year’s special (“The Abominable Bride“) connected to it, but was mostly a dream sequence.

Anyway, the point of all this is to iterate a point, which is that Sherlock will not coddle its viewers and let them get re-acclimated to the storyline. It dives right back in to the end of “His Last Vow,” and Sherlock having just murdered a person in full view of the police. And while that’s more or less swept under the rug, the nagging question is what the deceased Moriarty (who has, let me remind everyone, been dead since “The Reichenbach Fall” which ended series 2 in G-D 2012!) has in store for Sherlock in the weeks to come. That will surely be addressed in the third episode, “The Final Problem,” the actual Doyle story in which all the Reichenbach Falls story points happen.

Boy, lotta preamble. So let’s dive in. What I think a lot of people disliked about series 3 of Sherlock is that it sort of believed its own hype, got high on its own supply, and got much more into character drama–which fans love–without attaching it firmly to a Doyle plot. “The Six Thatchers” returns much more to that original style of storytelling, with writer and co-creator Mark Gatiss (who also plays Mycroft, of course) mixing together some lesser but still fantastic source material, “The Adventure of the Six Napoleons,” “The Sign of Four,” and some Holmeseian ephemera like Sherlock’s answer to the Kobayashi Maru test, “The Giant Rat of Sumatra.”

Gatiss packs in the plot, and in the show’s great tradition, uses disparate mysteries to connect to our main thread, but never really giving away which way we’re going. We’ve got several red herrings in this episode: first, the boy in “Tibet” dying while hiding in his car in his parents’ driveway; next, the idea that the breaking-and-entering simply to smash busts of Margaret Thatcher would have something to do with Moriarty; and failing that, the notion–which is actually the MacGuffin in “The Adventure of the Six Napoleons”–that the treasure inside the final bust was to be the valuable Black Pearl of the Borgias which Mycroft kept wanting Sherlock to find. All of these were to throw Mr. Holmes (and us) off the scent we couldn’t possibly have expected–that this episode would again tie to Mary’s past as a freelance assassin.

It’s long been reported that series 4 of Sherlock would more or less–save the odd TV movie or special–be the end of the show, owing to its stars Cumberbatch and Freeman becoming huge Hollywood names, both appearing in the Marvel Cinematic Universe as of this year. It very much seems to be heading that way, both for the season ending with the ominously titled “The Final Problem” and also what happens in this episode.

AGAIN A SPOILER WARNING

If we’d been paying attention, “The Six Thatchers” was actually about the marriage and new parenthood of the Watsons, and the lies they told each other. Mary, while telling John of her assassinhood, didn’t explain the full meaning behind the thumb drive on which was written A.G.R.A.–in the last episode, it was just meant to be Mary’s real initials, but in actuality, it’s the initials of Mary (aka Rosamund) and her three compatriots. While this seems to again be a pretty one-sided case of Mary lying and John finding out about it, we learn that John has been carrying on some kind of relationship with a Scottish woman he met on the bus. Parenthood changes a relationship, and John Watson wouldn’t be the first husband/father to have a wandering eye, but we always expect John to be better; even Mary near the end calls him perfect, which eats at him.

Easily the biggest shock of the episode is the death of Mary, saving Sherlock from a bullet fired by the found-out MI-6 secretary and secret-seller, Vivian Norbury. I truly did not expect that to happen, not least because it seems quite cheap to kill off a love interest–and new mother–not long after introducing her. But the death of Mary will add some huge dynamic shifts between Sherlock and John, with Sherlock feeling guilty–enough to talk to a therapist!– not keeping his vow to protect the Watsons, and John wracked with guilt over his affair, such as it was. Naturally they won’t be estranged for long, because there’s an episode next week, but things are not fun and frivolity the way they usually are.

I’m fairly gutted at losing Mary, but again, if this is indeed the end of the show, upping the ante all the way around is a good dramatic turn.

Glad to see Sherlock mixing character and mystery together again so well.

4 out of 5 sleuthing burritos

Case Notes:
– The episode was directed by Rachel Talalay, who has quickly become the best director on TV in her already long and accomplished career. Following four buh-rilliant efforts on Doctor Who, a couple on The Flash, and turns for both Supergirl and DC’s Legends of Tomorrow, she’s cemented herself as one of the best eyes in TV drama.

– The actor who played jaded assassin AJ is Sacha Dhawan. He’s one of the standouts in the episode for sure, and should be familiar to anyone who’s watched things written by Gatiss before, having appeared in both the Doctor Who docudrama An Adventure in Space and Time and the 2013 Ghost Story for Christmas, “The Tractate Middoth,” both also directed by Gatiss.

– “Sherrinford,” which Mycroft calls about after seeing the message “13th” on his fridge, HAS to be “the other one,” meaning the third Holmes brother. I refuse to believe it isn’t. Maybe it’s to do with Moriarty, but I sort of doubt it. But I’ve been wrong in the past.

What were your favorite parts of the episode? Do you think Sherlock REALLY didn’t know who Margaret Thatcher was? Let us know in the comments below!

Images: BBC/PBS

Kyle Anderson is the Associate Editor for Nerdist and an amateur sleuth of Encyclopedia Brown proportions. Follow him on Twitter!

Listen to what Gatiss told us about “the other one” in this video from Conival!