As John’s best man, Sherlock must deliver a speech to the happy couple, but has trouble gauging what is appropriate. He gives his speech by telling a number of anecdotes about their cases together and in the process unearths a threat at the reception.
18 months ago, Lestrade and Donovan are after a notorious bank heist gang but they get away with it. 12 months ago they get away with two million pounds. Six months ago, Lestrade still can’t get a conviction. Three months ago, they walk free again. Lestrade knows the only way to get them is to catch them in the act. Present day, Lestrade and Donovan are about to take down the gang in the act of robbery when Lestrade gets an urgent text from Sherlock: “HELP. BAKER ST. NOW. HELP ME. PLEASE.” Lestrade lets Donovan handle the bust as he runs to Baker Street, calling backup on the way. When he arrives, Sherlock desperately needs help writing his best man speech for John’s wedding. Meanwhile, police cars and helicopter swarm the area outside.
Later, Mrs. Hudson brings Sherlock tea as he composes a wedding song and practices his waltz. Sherlock and Mrs. Hudson talk about the wedding, how marriage changes people, and how Sherlock probably can’t expect to see as much of John. Sherlock rushes Mrs. Hudson out of the room, looks thoughtfully at John’s empty chair, then starts to dress for the wedding. Meanwhile, an distinguished and wounded soldier puts on his dress uniform.
John and Mary come out of the church after the wedding and the usual photos are taken. Sherlock talks with the maid of honor who is looking forward to putting his powers of deduction to use in finding the right man for the night. Later, the wedding party greets the guests coming into the reception. Mary’s friend David comes along and acts very standoffish toward Mary and then awkwardly notes that he’s met Sherlock before. There is a flashback of Sherlock screening David before the wedding, telling him that he’s too interested in Mary is only allowed to see her three times a year and always in the presence of John. Sherlock warns that he’ll be monitoring his behavior.
In the meet and greet line, Archie the ring bearer gives Sherlock a big hug. His mom notes that he’s really come out of his shell since Sherlock talked with him. There is a flashback to Sherlock giving Archie his ringbearer instructions. Archie asks if Sherlock has ever solved a murder and if he can see. Sherlock shows him pictures of murder victims, one with maggots in his eyes. Archie thinks it’s cool and Sherlock can’t deny it.
In the reception hall, Sherlock and the maid of honor continue to check out guys. John’s sister Harry is a no show at the wedding, but John’s ex-commander Major Sholto shows up. Sherlock and Mary look on as John and Sholto talk. Sherlock is a little jealous of Sholto, feeling a little left out. Mary takes his arm and notes that neither of them were the first in John’s life. Sherlock calls Mycroft to see if he’s coming to the “night do”, which he isn’t. Mycroft tells Sherlock that he won’t be seeing John as much now that he’s married.
Eventually Sherlock gets up to make his speech and has a pretty awkward start. In a flashback, Molly is concerned about Sherlock having to make a speech and is even more concerned about him having to read the “telegrams” of the people who couldn’t make it. Sherlock starts with those and has trouble getting through all the cute words of love and abandons them for his actual speech. When John asked him to be best man, he was initially confused. There is a flashback of John asking Sherlock to be his best man and Sherlock misunderstanding until asked directly, after which he stands completely catatonic for about 30 seconds. In his mind he said he was flattered and surprised, slightly daunted and coming very close to being moved, but never said it out loud.
Sherlock says all sorts of horrible things in his speech, aimed at making the point that he is a terrible person who never expected to have a friend, let alone one as brave and loyal as John. His speech is incredibly touching and makes the whole room cry, but he is completely surprised by this reaction and thinks he did it wrong. John hugs him and lets him know he’s doing wonderfully.
He continues on with his speech, looking to John’s blog for some funny stories. A flashback to “The Bloody Guardsman” shows Sherlock single-mindedly helping Mary plan the wedding while John looks for cases to solve. Mary fakes a phone call as an excuse to talk to John in the other room, telling him that Sherlock is terrified of the wedding, thinking that everything will change between them. Mary tells John to take Sherlock out on a case to show him everything is okay. Sherlock, of course, is in wedding mode and John has some trouble convincing him. They find a case about Private Bainbridge in the royal guard who thinks he’s being stalked, so they go to check it out.
Bainbridge isn’t off duty for another hour, so they sit and chat about Major Sholto, about how he’s a recluse who became hated when he lead some soldiers to their death and came out the only survivor. John reassures Sherlock that they’ll still be solving cases after he gets married. He also starts to tell Sherlock that he is one of two people who have completely turned his life around, but when he turns to look at him he’s already run off to infiltrate the barracks.
Meanwhile, John goes to see Bainbridge’s commanding officer, who is a very suspicious man. Meanwhile, Bainbridge is found dead in the shower stall after going off duty. As Sherlock tries to solve the murder, John discovers that Bainbridge is still alive and he ends up saving his life. Sherlock points out to his audience that the only element of the still unsolved crime that was truly remarkable was John Watson, who saved lives rather than solving crimes.
Sherlock then tells the story of John’s stag night, which was just the two of them going around to pubs. Sherlock asks Molly to calculate how much alcohol over how much time should be ingested in order to stay in the “sweet spot”. Sherlock brings two large beakers with him and calculates everything the whole night, but John secretly intervenes and gets them drunk. After only a couple hours they are back at Baker Street, snoozing next to each other on the stairs.
Mrs. Hudson comes along and asks what they’re doing back so early, so they go upstairs, drink some more, and play guessing games. Then a client comes in and they have a hard time staying awake through her story of a man she dated who turned out to be a ghost. They then stagger around through the possible crime scene and Sherlock is unable to deduce much beyond the very surface details of items and their uses, if not always what they’re called. The police come along and take them to the drunk tank where Lestrade wakes them up the next morning.
Sherlock goes back to work on the ghost boyfriend case, finding a large number of other women who have experienced the same thing. The man in question turns out to be a “Mayfly”, a man who surfs the obituaries for a one night identity in order to pick up women. The only thing Sherlock can’t figure out is the pattern between the women or the purpose of the Mayfly’s deceit, since he never has sex with the women. Sherlock digresses and starts to wind up his speech to the final toast, but then something occurs to him. The Mayfly client knew John’s middle name, but more than that, must have seen a wedding invitation at 221B to know John’s middle name. The Mayfly Man must have been trying to get information from the women he dated, very specific information about the wedding. Sherlock realizes that the Mayfly Man must be at the wedding and intending some kind of harm to someone.
While Sherlock has control of the room he makes everyone sit down and he rambles to keep his speech going while he roams the room trying to figure out who the Mayfly Man is. When this doesn’t work, he decides to figure out who the target is, and deduces it must be Major Sholto because he’s a recluse who has only come out for the wedding. All the women worked for Major Sholto at one time or another, but there was high turnover for extra security. Sherlock slips Sholto a note letting him know, so he retires to his hotel room. Archie gives Sherlock an idea about the connection between this and the Bloody Guardsman case.
Sherlock, John, and Mary follow Sholto and try to get him to let them into the room, but he refuses to put them in danger unless Sherlock can solve the case, which he does. Turns out that both Bainsbridge and Sholto had been stabbed hours earlier, but because of the belt on their military uniforms, nothing would have happened until the belt was removed. Sholto decides to let himself die, but Sherlock convinces him not to because it would be a terrible thing to do to John at his wedding. Sholto’s life is saved.
Sometime later Sherlock teaches the maid of honor to waltz and then confesses to her that he loves dancing. She wishes he wasn’t “whatever it is you are” and they share a look. Lestrade comes back with the wedding photographer, who is the Mayfly Man. He wanted revenge for the death of his brother, one of the officers who died because of Sholto. The rest of the reception goes off without a hitch. Sherlock plays the song he composed for John and Mary as they share their first dance, then makes a vow to always be there for “all three of you” and then swiftly corrects himself.
He then tells John and Mary that he thinks Mary is probably pregnant – the sign of three – but that they’ll be great parents after having to deal with him all the time. He sends them off to go dancing and then looks around awkwardly. He catches sight of the maid of honor, who is already dancing with another guy. Feeling out of place with no partner, he leaves the wedding reception and walks out into the night with the party music fading behind him.
Most episodes of Sherlock focus equally on very clever cases and the development of characters and their relationships. In this episode, however, the cases seemed to matter very little and took a back seat to John and Mary’s wedding itself. The bulk of the episode is made up of Sherlock’s best man speech, which is equal parts touching, funny, and awkward. Sherlock’s lack of understanding of people, traditions, and simple emotional reactions really comes into focus here and it is completely endearing in a way that we’ve never quite seen before.
His awkwardness is palpable, his mannerisms so restrained and childlike. When he discovers that his touching speech has made everyone cry, he doesn’t understand why. It is so telling that in a moment of social confusion he turns immediately, almost desperately, to John. “Did I do it wrong?” he asks, and John is there to reassure and help him along.
We also see a lot of how Sherlock sees himself. While he knows his talents and is deeply proud of them, often to the point of condescension and arrogance, he has come to understand what kind of man he really is – “a ridiculous man” – and how truly undeserving he is of the friends he has. There’s no telling what he may have endured or experienced during his time away, but it is certain that his image of himself as a man – a human being – has been largely shaped by John Watson. The fact that he didn’t realize or expect that he was John’s best friend is more than just the failure to understand social concepts and human emotions; it is, as he says, that he did not expect that a man like himself would merit friendship.
And in the very end, Sherlock’s awkwardness once all the wedding guests had partnered up to dance puts the sad icing on the heartbreak cupcake. We all know what it’s like to be Sherlock in that moment, the utter feeling of loneliness amongst the crowd; and what’s worse, to have no partner after confessing his love of dance. We all know exclusion, whether real or simply perceived. We all know that awkwardness, the uncertainty of how to engage in certain social situations. It is so painful to watch because we know that pain.
And for all this, Benedict Cumberbatch deserves extra appreciation for his performance in this episode. He conveys such childlike confusion and such painful awkwardness in such an endearingly beautiful way. While Sherlock is a confirmed high functioning sociopath, it has been noted that there’s an element of the autism spectrum present in his behavior, and that certainly comes out here. Cumberbatch walks such a fine line between the human and alien aspects of Sherlock and comes out on the right side every time. Of course, part of the credit must go to Sherlock’s writers and creators for a fine tuned script and a delicate understanding of their characters.
On a final note, how adorable is it that Sherlock is a master wedding planner? While it somehow makes complete sense, I never would have expected to see Mary and Sherlock diligently planning out seating charts and folding napkins while John sat on the sidelines looking for cases to solve. Who knew that Sherlock would rather plan weddings than go out crime solving? Brilliant.