You know the drill: massive spoilers for Sherlock 3×02, “The Sign of Three.”

Before getting bogged down in the dissection of the relationship intricacies of this episode (and believe me, I will), I want to reiterate how much I love the Doyle references in this show.  The title of this episode references the novel The Sign of Four, in which Holmes and Watson meet Mary Morstan.  In the novel, Major Sholto is Mr. Morstan’s friend and a somewhat villainous character.  Mary comes to Holmes to find her missing father (subsequently discovered to be deceased), which is how she meets Watson.  Jonathan Small is the novel’s main villain.  The episode tosses all of these elements together and mixes them up.  Major Sholto is now John’s ex-commander, the photographer’s name is Jonathan Small, and mention is made of Mary being an orphan.  The Sign of Four also includes a pygmy using a blowgun to shoot poisoned darts, which Sherlock references in his speech as the case of The Poison Giant.  Many of the cases Sherlock mentions (like The Hollow Client) can be found on John’s blog, a brilliant bit of advertising by the BBC (albeit clearly written by someone other than Moffat and Gatiss).  The Elephant in the Room is probably a reference to “The Mystery of the Vanishing Elephant,” an old Sherlock Holmes radio play from the 1940s.  Sherlock’s line, “Oscillation on the pavement always means there’s a love affair,” is paraphrased from the Doyle story, “A Case of Identity.”  In one scene, Sherlock hides cigarettes in the famous Persian slipper from Doyle’s stories and shoves it under the couch.  The writers continue to make oblique references to Mycroft’s weight, a nice little nod to his obese counterpart in the stories.  Sherlock continues to get Greg Lestrade’s first name wrong, particularly hilarious since Doyle only ever referred to him as G. Lestrade in the stories.

I love all of the detail.  One of the telegrams is from Mike Stamford, the guy who got the boys rooming together in the first place.  John still drinks out of the same old mug from the first episode of the show.  Mrs. Hudson asks Sherlock where he thought his tea came from in the mornings.  “I don’t know.  I just thought it sort of happened,” Sherlock says.  Later when Mary and John come out of the kitchen, Sherlock is sitting in front of a pile of folded serviettes.  “That just, sort of, happened,” he says.  Sherlock’s twinge when Mrs. Hudson sat in John’s chair was a nice little touch.  I thoroughly enjoyed the courtroom thought process (less cheesy than the mind palace approach) and the just-long-enough cameo by Irene Adler, complete with that same beautiful theme music.  Sherlock uses the code “Vatican Cameos” again from last season, itself a reference to an adventure mentioned in the novel The Hound of the Baskervilles, to alert John to danger.  In the middle of Sherlock’s rambling speech, he says, “I could go on all night about the depth and complexity of [John’s] jumpers,” a hilarious nod to the fandom’s obsession with John’s sweaters (and one that I completely missed on first viewing).

Speaking of unnoticed details, I’m going to beat this dead horse until nothing but bones are left: there’s something between Molly and Lestrade.  They’re talking together (sans Molly’s fiancé) on the lawn immediately before the reception and in the background of almost every shot of the reception.  It would be harder to spot if Molly weren’t wearing some kind of ridiculous yellow banana peel on her head.  She sits closer to Lestrade than she does to her own fiancé.  I got a kick out of the fact that Molly cottoned to the inherent problems of Sherlock being best man before anyone else, and hunts down Lestrade and Mrs. Hudson to try to solve the problem.  I adore Molly.  She appeared to be actively performing an autopsy while talking to Mrs. Hudson, and you have to admire someone who can handle a phone and a bone saw at the same time.

Okay, on to the big stuff.  Opinion seems to be somewhat divided on this episode.  “The Sign of Three” is clearly destined to become a fan favorite, on the one hand—it has everything the fans have been wanting to see.  As I watched, I realized… this isn’t television: this is live-action fanfiction, complete with a John/Sherlock hug.  At the same time, some people felt that there was entirely too much warm fuzzy coming out of everyone’s favorite consulting detective to be completely believable.

On first viewing, I felt like the episode, while eminently satisfying, did feel a little out of character for Sherlock in spots, but upon rewatching, I’ve revised my opinion.  When confronted by the prospect of “losing” his friend, or at least his undivided attention, Sherlock could have realistically reacted in two ways: 1. Go to every effort to sabotage the wedding, snub John for his “betrayal,” and retreat in high dudgeon into a life of loneliness, or 2. React the way Sherlock did in the episode, being as supportive as possible in an effort to remain a part of John’s life.

The second option is clearly the more mature one, and implies the same fear of change with the addition of some marked character growth.  Yes, Sherlock was a jerk in the first episode of the season.  But time has passed (we know he returned around Guy Fawkes’ Day in November, and the wedding is in May), and he has a clear respect for Mary (who manages both men with an almost uncanny ease: “I’m not John, I can tell when you’re fibbing.”) and concern for John’s happiness. As for whether all of this feel-good fluff is consistent with Doyle’s character, I don’t think that even factors in: Doyle’s Holmes was always a kinder, more sensitive gentleman than Sherlock ever was, and this incarnation has already established itself as a very different character.

And this Sherlock is very frightened of change, while simultaneously wanting his friend to be happy in his new life.  Everyone from Mycroft to Mrs. Hudson tells him that things will never be how they were. The happy couple are the exception to this rule: John assures him that everything will remain the same, and Mary tells him that “neither one of us were the first, you know,” presumably meaning there’s room for more than one person in John’s affections.  She certainly doesn’t seem threatened by Sherlock’s and John’s relationship, and, interestingly, Sherlock seems less threatened and more wistful when he sees her and John together.  He does initially seem to feel threatened by and certainly jealous of John’s relationship with Major Sholto, perhaps because he feels it’s more similar to the one he has with John. Sherlock calls Sholto John’s “previous commander.”  John says, “Previous suggests that I have a current commander.”  “Which you don’t.”  “Which I don’t.”  And yet, John’s relationship with Sherlock is not unlike that of a trusted soldier and his commander: John has a lot of trust, respect, and admiration for Sherlock, and he even saluted after his little speech at Sherlock’s grave.  Sherlock acknowledges that he and Sholto are very much alike, and this realization enables him to talk Sholto out of killing himself: “We wouldn’t do that, would we?  We would never do that to John Watson.”  Rather telling little first person plural, there.

Sherlock is forced to face what John means to him when he thinks that he might lose him (or at least lose his undivided attention), and the episode showed this beautifully.  It seems to be triggered by the realization that Sherlock is in fact John’s best friend, something Sherlock can’t even fathom.  He’s blindsided by the fact that John cares about him—and possibly just as blindsided by how much he cares for John.  Hearing him talk about John the way John talked about Sherlock at his grave was very, very satisfying. Sherlock is fully aware of his own shortcomings, as he illustrates in the speech, and fully aware of John’s strengths: “I will solve your murder, but it takes John Watson to save your life.” John whispers to Mary, “If I try and hug him, stop me.”  “Certainly not,” she says.  At the crucial moment, Sherlock rejects the voice of Mycroft in his head (the voice of cold, merciless logic) and turns to John and his humanity.  “John Watson, you keep me right,” he says, realizing that saving a life is more important than solving the mystery.

The hilarity of the failed stag night (“He’s clueing for looks.”) masks what is actually a very sweet gesture, and highlights one of the themes of the episode: Sherlock is trying to do all of this folderol right for John’s sake.  Composing the waltz, vetting the wedding participants, and folding serviettes (!) are all ways he can serve—and be included.  He has to be told to get out of the photo of the bride and groom, and he stands in the receiving line with them when none of the bridesmaids do. What will this new relationship be like?  After all, as John says, “We can’t all three dance, there are limits.”  Initially it seems as though the title of the episode is referring to this new dynamic between the three of them…until the end, when it’s revealed that Mary is pregnant, and the “three” in question are all Watsons.  Sherlock leaves the wedding early and alone, putting on his heavy coat—purely for drama, since we already know this was a May wedding.

So, predictions for the finale.  I avoid the BBC trailers like the plague because they give away too much, but I expect obscene amounts of angst and the obligatory cliffhanger.  The title of the episode is “His Last Vow,” a play on Doyle’s story “His Last Bow,” Holmes’ last case before retiring.  Sherlock’s one and only vow at the end of “The Sign of Three” is to always be there, no matter what, for the three Watsons.  It’s safe to say John or Mary or both will be in danger in some way, requiring a sacrifice on Sherlock’s part to save them.  I suspect Mary’s secret(s) will be involved in some way, and we know that Magnussen will be back. In the books, Mary dies during the interval between Holmes’ “death” and his return in “The Adventure of the Empty House.”  I desperately hope the writers don’t kill her off.  We never see what happens to the Waters family, although presumably Donovan (who has not, after all, been fired, though she seems as sour about Sherlock as ever) arrests them.  If they wriggled free again, perhaps they’ll play a role.  Mycroft’s enigmatic comment about Redbeard will probably be explained at some point.  I’m not sure if that was a reference to a childhood toy/pet or a reference to his comment last season about Sherlock wanting to be a pirate as a child.  We shall see…