Sherlock season 4 is returning on January 1, 2017. The fandom only had to wait 3 years to find out what happened following the dramatic, Moffat-style cliffhanger ending to season 3. Sure, we got the New Year's special "The Abominable Bride" in 2016, but it hardly answered any questions we were left with after watching "His Last Vow".
Moriarty's return is hinted at in the season 3 finale; however, in "The Abominable Bride" Sherlock (Benedict Cumberbatch) is convinced that Jim Moriarty (Andrew Scott) is in fact dead. (After all, he took a bullet to the brain in season 2 finale). However, Andrew Scott has been cast in season 4, meaning that Moriarty has come back in some form.
Still, whether or not Moriarty is back, "something is coming" according to Sherlock in the first season 4 teaser trailer. My money is on Toby Jones, who has been cast as Culverton Smith in the episode "The Lying Detective" (episode 2). In Sir Arthur Conan Doyle's novels, Culverton Smith was the antagonist in The Adventure of the Dying Detective, which is likely what the episode is based off of. In the novel, Sherlock is dying (SPOILERS: it's a trick to catch Smith) and Watson tends to him. This could explain the hospital shot with John Watson (Martin Freeman) from the first teaser trailer.
The hospital scene could also be because Mary (Amanda Abbington) is in the hospital. After all, she was pregnant at the end of season 3 (remember "The Sign of Three"?)
In the first teaser trailer, Molly Hooper (Louise Brealey) finally blows up at Sherlock. We have seen her progress from season to season--she even slapped Sherlock in season 3. In the trailer, she tells Sherlock that "it's not a game" possibly alluding to the interaction between Moriarty and Sherlock in seasons 1 and 2, which Sherlock referred to as a "game" or "chess". What could upset Molly this way?
Molly isn't the only one who breaks. Mrs. Hudson is clearly upset with Mycroft Holmes (Mark Gatiss), calling him a "reptile" and ordering him to leave her home. What could possibly make Molly Hooper and Mrs. Hudson both snap?
As for the second teaser trailer, it's clear that the past is far from passed. As Mycroft tells Sherlock in the opening scene, "The roads we walk have demons beneath. And yours have been waiting for a very long time."
What exactly are Sherlock's demons? Could it be he's into drugs again? Or has something come back to haunt him from when he faked his death in season 2? Or perhaps (SPOILERS) it has something to do with They Lying Detective, if he does in fact fake his death once again, like in Sir Arthur Conan Doyle's story? Whatever the case may be, Mycroft clearly disagrees with his brother's plan. He asks, "What is this? We can't do this. Is this supposed to be a game?" (Once again alluding to the 'games' Sherlock likes to play). Could it be this new "game" is him faking his death once again in order to trick Cultervon Smith?
Watson also seems disappointed in Sherlock. "I thought this was some kind of trick," he says, to which Sherlock replies, "It's not a trick, it's a plan." What trick is Sherlock playing? Is it a new trick, or a "demon" from his past?
Much like Moriarty in "The Reichenbach Fall" (season 2, episode 3) Cultervon Smith seems determined to target Sherlock's closest friends (and, perhaps, his family, as his parent's house is on fire in the trailer). He also understands the importance of secrets, much like Magnussen in season 3. He says to Sherlock, "What's the very worst thing you can do to your very best friends? Tell them your darkest secret."
What secret is Smith alluding to? It could be drugs, or it could be something that even the viewers know nothing about. (In fact, we may never find out what Sherlock's darkest secret is).
The trailer ends with Sherlock saying three words: "I love you."
Who is he talking to? (The fandom has many 'ships' involving Sherlock--although, sorry Johnlock shippers, both John and Mycroft are seen standing behind Sherlock when he says this.)
Is it a trick? (Like the time he actually proposed to a girl in season 3, only for a case.)
Why is he saying this? (What could be so important that he feels he needs to say "I love you"--is it to save his friends? Is he being held captive? Are his friends being held captive?)
Regardless of why he says, "I love you," it is a big step for Sherlock. Whether it's to save his friends or because he actually means it, Sherlock cares enough to say those three words. I repeat, let it be known that Sherlock cares.
