Months ago, executive producer Steven Moffat teased fans about his "devastating" plans for "Sherlock" season 4 in 2016.

Now, it's Sue Vertue's turn to tease "Sherlock" fans. Last Saturday, she tweeted a photo of the Sherlock Christmas special script written by Moffat and Mark Gatiss.

"This is what we've been doing today! Later on a pic of Sherlock and John as they'll appear in the Special #221back," Vertue posted on Twitter.

She fulfilled the promise soon after with a photo of Benedict Cumberbatch and Martin Freeman in Victorian-era-like clothing.

Will they be incorporating a little of 'Dr. Who' in the one-off special set for December next year? Moffat is also the creator for the long-running time travelling BBC series.

Or will they be using the original time frame (1800s) in Sir Arthur Conan Doyle's celebrated detective series?

Aside from the update for the intriguing Christmas special episode, Gatiss also revealed some very vital information to Radio Times recently.

"Expect tragedy as well as adventure, that's just how it goes," the executive producer who also plays Sherlock's brother, Mycroft, teased about the upcoming 'Sherlock' season 4 plot line.

Gatiss added that although they're following Doyle's general arc, they're storyline so far has "gone quite a long way away as well."

Avid fans are therefore wondering if Mary Watson's death (which Doyle wrote of in the stories) would be written off in this modern adaptation. Martin Freeman (who plays Dr. John Watson), however, had previously hinted about Mary's death "at some point" in accordance to the original story.

If they do follow the original story arc then Watson could be moving back to the apartment with the genius detective. Will he then be losing both his wife and baby?

Then again, the BBC series has already dabbled with fake (and highly orchestrated) deaths in season 3 for Sherlock himself and now for Moriarty. Will they do the same for Mary? More importantly, will fans see Watson's baby?

Tell us what you think will happen in 'Sherlock' season 4? Do you think Watson should be subjected to watching two of his loved ones (convincingly) die right before his eyes?