The greatest detective will have everyone waiting until 2016 before he returns to television screens. While Santa Claus was nowhere near Sherlock and his world this holiday season, fans would be happy to know that a Christmas special is in the pipeline. Carter Matt revealed that the "Sherlock" cast and crew will be gathering in January 2015 to film a holiday-themed episode that will be aired on Christmas 2015. That is still about 365 days away, but having something to hold on to is already making the entire wait well worth it. 

Meanwhile, the fourth season of "Sherlock" has a long way to go but rumor mills are on top gear in foraging what will happen upon the show's comeback. Showrunner Steven Moffat has been dropping hints in his interviews and speculators try to piece them all together to create a big picture on what's coming to Sherlock Holmes. 

Moffat is "reasonably confident that the very next thing to happen to Sherlock and John, is the very last thing you'd expect." And with good ideas ready, this might lead to a dark storyline, too.

"We have a plan to top it [Season 3]. And I do think our plan is devastating. We've practically reduced our cast to tears telling them the plan. We're probably more excited that we've ever been about Sherlock," Moffat told Entertainment Weekly.

If there's one key word in his statement, it would have to be "devastating." Following Sir Arthur Conan Doyle's original tales, this only hints on a character's death. The likeliest one to be on the receiving end is John Watson's love, Mary Morstan. This is backed by Martin Freeman's statements on Telegraph. 

"While we play fast and loose with the original stories, we generally follow the trajectory of what Conan Doyle did. So [Watson] gets married, and then Mary dies — so at some point presumably she'll die," Freeman, who plays Dr. John Watson, revealed. 

With Mary being a potential goner, the show may again welcome Irene Adler. After all, Benedict Cumberbatch, who portrays Sherlock Holmes, would "love to have her back."

"Sherlock is Mark Gatiss and Steven Moffat's passion project. If it fits to have her back, I know they'll write it; if it doesn't, I trust them to get it right," Lara Pulver, who plays Irene Adler, told Radio Times.

But she's not the only one pitted to show up. Another Holmes brother, Sherrinford Holmes, might turn up, too. Moffat is mum about this bit of detail though. Many fans believe (or wish) that Tom Hiddleston, who played the crowd favorite villain in "Avengers" and Thor's power-hungry brother Loki, will assume the role. 

Lastly, what could become of the clever gentleman's love life? Rumors indicate that the new season may give Molly and Sherlock a chance at romance. However, the return of his temporary love, Janine, may make things complicated. Moffat told IGN that "he'll see her again."