I think the Rat episode may be a mashup of Empty House and Boscome Valley, for the admittedly silly reason that each has a character named Moran; no real connection, I know, but I think Moftiss could make one. (Someone else said this too in another thread, but they had better reasoning for it  )
I sort of dread Wedding, because I think they could marry John off, just because one of them ( think it was Gatiss) said that most Holmes serials ignore John's marriage which is a 'lazy' way of doing it, 'people don't flat-share forever'. (I will try to find the interview, there is a link to it somewhere on this forum, I think).
I think Bow has to be His Last Bow, but I don't think that excludes the possibility of a fourth series; Moftiss are not that strict about the cannon, and I can absolutely see Mycroft recruiting/gangpressing the boys into an undercover operation against a terrorist cell. Keeper, I would love to see Sherlock unwillingly and ungraciously knighted! Hopefully he'd dress for the occasion ( as opposed to forgetting his trousers). 

Plus, they have barely touched on The Sign of Four, just here and there, it really is a major story.  Perhaps Sherlock comes back to find John engaged, moving on with his life. It would be easier for him to sustain a relationship with Sherlock gone.

I wouldn't be surprised if they did "The Speckled Band," seeing as it is Moffat or Gatiss's (sorry, forgot which) favorite story, and they haven't even referenced that yet.

Davina wrote:

They have referenced it though. In The Speckled Blonde scene and mention in John's blog. Remember?

I've been wondering about that-- do they not intend to do the stories they referenced as joke titles for John's blog, and do they not intend to do the ones referenced in the online companion-to-the-show blog?

Davina wrote:

They have referenced it though. In The Speckled Blonde scene and mention in John's blog. Remember?

Yes, I remember, but that does not mean they cannot use the story in another episode. They would have to change the story anyway if they would want to use it as its own episode, because the Speckled Band is only a short story.

Yes, it was in A Scandal in Belgravia that John coins the case "The Speckled Blonde".

I imagine that wedding is a reference to the Noble Bachelor. Most likely Rat will involve Sherlock returning in a mix of The Empty House and Boscombe Valley (as has been mentioned before), along with the discovery that John is engaged (possibly some Sign of the Four reference as well with Mary).

Wedding will be the undoing of John's engagement via the Noble Bachelor.

Yeah, Speckled Band is Moffat's favourite. He said they might do parts of it in the future although he was fairly ambiguous and mysterious as ever.

I'm sort of coming round to the idea that it MIGHT be John's wedding they're referring to...At first I thought it would be too obvious, because EVERYONE is going to think of Mary Morstan & John, but then, the three words they gave us last year were really easy to work out - WOMAN, HOUND, FALL - even a casual Sherlockian would have been able to guess them.

So I don't know whether people are trying to read too deep into it, and we should just "say what we see"...so BOW is His Last Bow. They've obviously done that on purpose to make us all think that Sherlock is going to retire and start keeping bees, but they could basically just adapt the general storyline without retiring the guy just yet...WEDDING is John's wedding and yes I really would like to see them mix it with another storyline somehow though, maybe Noble Bachelor...I still really want it to be Milverton, but there isn't an actual wedding in that one, just an engagement. It makes sense for RAT to be Boscombe Valley.

Actually...I just read a really good post by someone on this theory website, that made me change my mind again about the whole John/Mary wedding thing:

http://www.hypable.com/2012/08/24/sherlock-series-deducing-rat-wedding-bow/

I don't really understand the idea that the second story will include John's getting married to Mary.

The second word is "wedding," not "marriage," and no ACD story includes a wedding for Watson. In "Sign of the Four," Watson proposes, but doesn't marry. Later he's referred to as being already married, but the wife isn't named: she may or may not be Mary Morstan. She is already dead by the time Sherlock returns from his own "death." Several later stories refer to Watson's being married, presumably to one (or more) other women.

Also, practically every major element of "Sign of the Four" has already been done in "The Blind Banker." Given how few episodes are made, is it likely that Moffat and Gatiss will do a second episode involving stolen treasure from the east being re-stolen by one of the crooks who is then killed by one of the original criminals who has a sort of pipe that shoots a deadly projectile and who has small feet and hands and who is a sort of acrobat climbing walls and running across rooftops in search of the treasure, part of which is a small gem that has been given to a woman who doesn't know of its origin? Why, "The Blind Banker" even includes a pair of feuding siblings, and a scene in which John and his new girlfriend cling to each other in a moment of dangerous excitement - again, all right out of "Sign of the Four."

"The Adventure of the Noble Bachelor," "A Case of Identity," "The Speckled Band," "The Solitary Cyclist," "The Illustrious Client," and "Lady Frances Carfax" all contain plots that focus in some way on a wedding (just past or planned). Any or all of them seem more likely for the "wedding" clue than "Sign of the Four."

They've already used an acronym in Hound so it is unlikely they will do the same again.

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