Sherlock is renowned for delivering high quality drama, and although the seasons are very short and a new one doesn’t come around all that often, when a new set of episodes does drop they're bound to be talked about for a long time before and after airing. In fact, it’s been almost three years since Sherlock season 3 aired at the start of 2014, with a Christmas special, “The Abominable Bride” shown on January 1st, 2016. When we last saw Sherlock on our screens, he was re-emerging from his mind palace and declaring that he knew what Moriarty’s next move would be. But isn’t Moriarty dead?

Yes, this time around it seems as though Moriarty might really be dead after all, but that doesn’t mean Andrew Scott won’t appear in season 4, which will make its debut on New Year’s Day, 2017. As ever, a lot of season 4 remains shrouded in mystery, but there are some clues and teasers out there, which give a fair idea of what we could expect.

Episode 1: The Six Thatchers

Sherlock Season 4 Photos Baby Watson

The main theme that keeps occurring in comments made by cast and crew, is that season 4 is significantly darker, but showrunner Steven Moffat has also said that we do have the trademark Sherlock humor to look forward to as well. The first episode of the new season, titled “The Six Thatchers” sees Sherlock returning to England, and Mary and John Watson becoming parents. Mrs. Hudson, Molly, and an entirely unhelpful Sherlock placed an announcement of the birth in British newspaper, The Telegraph, revealing the baby’s name to be Rosamund Mary Watson. A season 4 photo released seems to suggest that being an uncle is not something that comes naturally to Sherlock, since he looks entirely perplexed by such a small human. However, it looks like Sherlock might get along better with a four legged friend - his own hound, to be precise.

Rosamund Watson Birth Announcement
Via Radio Times

The episode is written by showrunner Mark Gatiss, who also reprises his role of Mycroft Holmes. The title is based loosely on the Arthur Conan Doyle Sherlock Holmes story, “The Six Napoleons.” In that story, Lestrade features heavily as he tries to solve the mystery of who is smashing busts of the historical figure in order to find a hidden pearl. Moriarty’s demise is once again confirmed in the synopsis for "The Six Thatchers," which says that Sherlock is waiting for his arch-nemesis to make his “posthumous move.”

Picking up on the themes from Doyle’s original work, this time around Sherlock is helping Scotland Yard to find out who is destroying images of the late former U.K. Prime Minister, Margaret Thatcher. “Is there a madman on the loose?” the synopsis reads, “Or is there a much darker purpose at work? Something with its roots deep in Mary Watson’s past…” That last line suggests that once again, Mary Watson’s life pre-John will have a lot to do with the overriding arc of the season. We already know she was an assassin, and assumed a false identity in order to escape her former lifestyle. Could it be that someone has caught up with her?

Episode 2: The Lying Detective

Sherlock-Season-4-Culverton-Smith

“The Lying Detective” is a title based on another of Doyle’s stories, “The Dying Detective,” and will introduce new villain Culverton Smith. Toby Jones (Captain America: The Winter Soldier) - an actor renowned for his great character work - will be assuming the role and, given the description of Smith, it sounds like we’ve got a lot to look forward to. In the story, Culverton Smith uses his knowledge of tropical diseases to kill his nephew before attempting to poison Sherlock. Believing Sherlock to be dying, Smith visits him and confesses to all he has done, only to discover that it was all a ruse. Whether that will all play out on screen or not, remains to be seen, but we do know that Culverton Smith is set to be possibly the most evil villain Sherlock has ever seen. Gatiss describes him thus:

“Toby [Jones] is doing something very interesting. He’s an avuncular, funny seeming man with terrible teeth. We’ve given him terrible teeth, which are symbolic of the rot inside him. It’s a great complex, shaded character. You’re not quite sure what the relationship is with him.”

Moffat agrees, and surely, with such descriptions from both showrunners, Jones must be playing someone truly vile.

“This guy is the purest evil. Sherlock is actually appalled by him. He’s the most evil villain we’ve had. I don’t think that when you see it, you will disagree. He’s horrific.”

Really, we don’t know anything more about episode 2, but Gatiss and Moffat’s comments are enough to make sure we’ll be tuning in. Their remarks are in keeping with the “dark, tough” theme that keeps arising whenever season 4 is discussed, but it sounds as though the BBC’s Culverton Smith must be much more evil than Doyle’s version. After all, poisoning your nephew and attempting to kill a self-proclaimed high functioning sociopath is pretty tame behavior given all that we’ve seen from Moriarty and Magnussen in previous seasons. If episode one is the scene setter, episode 2 could be viewed as the entertainment, which leaves….

Episode 3: The Final Problem

Sherlock season 4 - Jon and Sherlock

If all is to be believed, the final episode of the season could well alter the Sherlock universe completely. Just the title is ominous enough: “The Final Problem.” Certain comments made by Cumberbatch suggested that this might be the end of the series, but the actor and Moffat have both since clarified that the show will not be finishing altogether. However, they have also said that there will be a long gap before the show returns. Though that is hardly unusual, this time there is a reason within the episode as to why Sherlock will be absent for so long, as Cumberbatch explained: "It goes to a place where it will be pretty hard to follow on immediately,” while Moffat told press: "You’ll have to see the fourth season to realize why, for now, [new series are] not going to happen again at the same regularity that it has been happening."

“The Final Problem” is the title of one of Doyle’s stories, where Sherlock meets his alleged end in a plunge from the top of the Reichenbach Falls with Moriarty. Of course, that storyline has already been done, with Sherlock’s staged fall from the top of the hospital, so we can’t expect a repeat. However, the story also focuses on the rounding up of all those who worked for Moriarty, so we could see Sherlock finally putting a definite end to Moriarty’s games. Certainly it seems reasonable to expect some kind of Moriarty-based storyline during this fourth season, but though “The Final Problem” might draw influence from Doyle’s story of the same name, there really is only one event that could stun Sherlock and Watson into a long period of submission, and that is the death of Mary.

The idea isn’t out of left field; in Doyle’s canon Mary does die at some point after the end of “The Final Problem,” but her death is only mentioned in passing. Mary Watson doesn’t have such a prominent role as she does in Sherlock, though, and it would be absurd to think that the show wouldn’t dramatize such an event. The death of Mary would, of course, have a profound effect on John, as he would be left alone with the baby, but Sherlock would also feel the loss; both on behalf of his friend as well as for himself - he might not always show it, but he really is quite fond of Mary. Depending on the circumstances of her death, there might also be a blame game played out between the two which could well damage their relationship.

Sherlock season 4 - Benedict Cumberbatch

As well as it being canon that Mary dies, Martin Freeman has previously stated that he assumes Mary’s death will happen at some point in the show, since Sherlock loosely follows the same timeline. Couple his comments with a tweet from Amanda Abbington which showed Mary’s wedding ring and referred to her ‘golden wrap’ (common parlance for the final scenes of a character), and it seems like a very probable plot line that we could expect, but there’s one more character that we could see appear in Sherlock, which would really deliver a twist.

The clues given for the three episodes of this season were “Thatcher, Smith, Sherrinford.” The first two are taken care of, leaving Sherrinford as the clue for “The Final Problem.” A fictional biography of Sherlock Holmes, by William Stuart Baring-Gould brought to life a third Holmes brother with the name Sherrinford and, though he’s never been alluded to by Doyle, he has been mentioned (though not by name) by Mycroft Holmes in season three when he told Sherlock “I’m not given to outbursts of brotherly compassion. You know what happened to the other one.”

Given that Sherlock and Mycroft are pretty complex individuals, what could Sherrinford Holmes be like, were he to appear? If he does show up, might he be somehow involved in Mary’s death if it happens? It’s all speculation, and there are so many theories, thoughts, and opinions out there that it’s hard to sift through it all. Then again, the secrecy coupled with the speculation is what makes Sherlock so great. The game, as they say, is afoot.

Sherlock season 4 starts on BBC 1 and PBS on January 1st, 2017.