Due to "Sherlock" stars' Benedict Cumberbatch and Martin Freeman's busy schedules, "Sherlock" season 4 won't be released until after next winter.

It is said that there is a Christmas special in the works that could air as early as  December 2016. Some sources claim the Christmas episode may be based on Sir Arthur Conan Doyle's "The Adventures of the Blue Carbuncle."

While writing of the episodes hasn't commenced yet, the team seems to have a good idea of what is going to happen, in which, writers and producers have been echoing the same sentiment  - expect tragedy.

Many have speculated that this may mean the death of Mary Morstan because this is what happened in the book; however, this may not be the case as according to Screenrant, Gatiss has said, "Just because it's in the stories doesn't mean it'll happen in the series because there's an awful lot of changes and an awful lot of places to go and things to do. It should be clear by now that while, of course, Doyle is our absolute god, we have gone quite a long way away as well [...] So there are lots of surprises to come." He went on to add that this season will take Sherlock and Watson into "deeper darker water."

Another element that "Sherlock" fanatics have desperately wanted to know is the return of Moriarty, which was hinted in the last few seconds of season 3. Producers have remained cryptic on the subject though hinted that its not exactly what viewers think.

Recently, Gatiss posted a Twitter photo of a store sign that reads "Jabez Wilson, Pawnbroker, Est. 1854," with an ornate blue vase behind the glass.

"We Gingers must stick together...#Sherlock," he captioned the cryptic tweet posted Tuesday. This sent Sherlock fans into a tailspin, speculating that the Christmas special will be based on "The Adventure of the Red-Headed League."

"Sherlock" season 4 won't arrive until 2016. Check back often for more "Sherlock" season 4 news and updates.