My, how time does fly in the Sherlock universe. Only last week, the super sleuth returned from the dead and John Watson proposed to Mary Morstan, and now it’s already six months later and time for the pair to be married, with Sherlock giving the best man speech. Hilarity and horror, eh? “The Sign of Three,” written by Steve Thompson with contributions by Steven Moffat and Mark Gatiss and directed by Colm McCarthy, is probably one of my favorite episodes of the series, full stop. It brings together disparate threads that you might not think are significant until suddenly they are, and it all wraps up in a clever and satisfactory way. I fear that, like “The Empty Hearse,” some people might not enjoy that style of storytelling and feel gypped that they didn’t realize they were watching the mystery they were watching, but that’s the beauty of Sherlock, I think. You roughly know what you’re getting from a “Hounds of Baskerville” or “A Scandal in Belgravia,” but not “The Sign of Three.” Could any of us have guessed?

The episode begins with a little vignette in which Inspector Lestrade (Rupert Graves) is having a hell of a time trying to catch a gang of bank robbers. After months of not getting the evidence to stick, he and Sgt Donovan finally have the gang dead to rights, but before the arrest can be made, Lestrade receives a text from Sherlock beckoning him urgently to Baker Street. Lestrade, dutifully, sprints over with a full police backup, only to find that Sherlock just needed help writing his best man speech. I love this little bit because it illustrates both how utterly clueless and self-centered Sherlock is (as if we needed more evidence of that) and how highly Lestrade regards Sherlock. He would drop a six-month-old case just because Holmes beckons.

The bulk of the episode is told in a series of flashbacks depending on various different things regarding the lead-up to John and Mary’s wedding. We actually don’t even get to see the ceremony, and I think that’s interesting in sort of the way Sherlock mentions to Mrs. Hudson: Two people who live together got dressed up, said some words, will go on holiday, and then continue living together. The nuptials are sort of incidental to the larger story, that of Sherlock’s speech bringing in two separate stories that seem wholly disconnected but are eventually shown to be of utmost import with regard to a mystery in the present we didn’t even know was happening.

First, for the character-y stuff; Mrs. Hudson, Molly, and Lestrade are all really worried about Sherlock giving the speech because, well, because he’s a crazy person. This is pretty adorable, it has to be said. At first it seems like their fears are well-founded when his speech begins in a perfunctory and insulting manner, but eventually it becomes really sweet in a robotic and alien sort of way. He’s also sort of rude to Mary’s bridesmaid Janine, though he eventually helps her find someone with whom to hook up.

There are really lovely moments with all of the supporting characters, again like last week, with special commendation again going to Una Stubbs as Mrs. Hudson, who cavalierly talks about her former husband running a drug cartel in Florida and being arrested for blowing a guy’s head off. Really nice, that. We also have fun things with Lestrade in which he clearly doesn’t understand a lot of the mystery, and with Molly, who is aghast and embarrassed any time her boyfriend, Tom, the Sherlock surrogate, says something dumb.

We also see flashbacks to two different mysteries (clearly of recent memory) that have to do with humorous stories about John, the first being “The Bloody Guardsman,” about how a young Palace guard was stabbed in a locked shower stall after worrying he was being stalked by a photographer. This story illustrated just how good a man Watson was, saving the man’s life while Sherlock failed to solve the mystery. The second is “The Mayfly Man,” in which Sherlock and Watson go out for a stag night and end up taking on a case for a woman who can’t find a guy she went out with once, but do so completely wasted. In both instances, John and Sherlock’s friendship is brought to the forefront, and we see that Mary wants them to continue working together because she knows they both need it. They’re very nice little character pieces and are delightful to watch.

But then, BOOM, we get a big piece of mystery on which Sherlock picks up from talking about these two cases, which are suddenly connected, and he discovers that John’s former commanding officer, who was badly wounded in Afghanistan and who inadvertently led a battalion to their deaths, has been targeted for murder at this very wedding reception. The title “The Sign of Three” is very apt for this reason; It’s three seemingly unrelated events that are totally related but are only known to be related because they were talked about at the wedding. Convenient? Sure. Enjoyable in spite of that? Absolutely.

What the episode does immensely well is to show Sherlock’s mind work in a dynamic visual way. When he’s trying to figure out why those women were all targeted by the Mayfly Man, even though he’s just talking to everyone on laptops, we see it represented in a huge government room, to which he returns when he’s trying to piece everything together. Mycroft shows up to be a focal point of assistance, and there’s even a momentary glimpse of “The Woman,” which he quickly dismisses. The series has always done really well at making scenes of thinking exciting, and this episode did it better than probably any of the other ones.

While the resolution of the mystery is maybe secondary to the pomp and circumstance of the event, it nevertheless works on all of the levels at once, even if we can’t see it right away. The final scene of dancing, and the revelation that Mary is pregnant, is a really nice moment for all of the characters to just be with each other before Sherlock, alone again, despite his love of dancing, walks off into the night.

Ultimately, this episode works better on its own than did “The Empty Hearse,” but that’s largely by its nature. The premiere had to wrap up cliffhangers and bridge a two-year gap, whilst this one simply had to tell one story of one guy giving a speech at his best friend’s wedding reception. The relationships between the characters this year is clearly more important than the mysteries, but that’s not necessarily a bad thing. If we look at the whole show, with its feature-length episodes, then with Series 3, we’re already up to the 7^th and 8^th movie, and eventually you find that the characters are what keep people watching and the mysteries are there to dazzle in spurts. The world of these people is one that I’d definitely like to stay with, and it’s not just because people solve murders.

The downside of this show’s format of 90 minute episodes is that we’re already almost done with the series for another year (or possibly less than a year if they end up doing a Christmas special), but for all the amount of content they pack into the episodes, we get several regular-sized episodes’ worth of story. Next week, it’s “His Last Vow,” written by Moffat and directed by Nick Hurran, the team behind, among other Doctor Who episodes, “The Day of the Doctor.” On what sort of cliffhanger will this series end? We shall see in a short week’s time.