After the release of the Holiday special episode titled "Sherlock: The Abominable Bride," fans are now wondering what's next for the clever detective when the series returns for its fourth season.

Speculations say the story about Sherlock Holmes's (Benedict Cumberbatch) beginnings will be tackled in "Sherlock" season 4. However, the confirmation will not be released until the series returns next year.

In a previous interview with Entertainment Weekly, series co-creator Steven Moffat revealed that more mysteries will be solved in the upcoming season.

"There are answers coming to questions which nobody has asked. There's one thing that no one has really brought up," Moffatt explained.

He also revealed that the theme for "Sherlock" season 4 will dwell on "consequences," saying, "It's dark in some ways—obviously it's great fun and a Sherlock Holmes romp and all that—but there's a sense of... things... coming back to bite you. It's not a safe, sensible way to live. It's hilarious and exhilarating some days, but some days it's going to be bloody frightening."

Other speculations about the plot of "Sherlock" season 4 mention that the season will possibly show the death of Watson's (Martin Freeman) wife Mary (Amanda Abbington). Viewers of the show found out that she was pregnant during the third season finale. But in the novels written by Sir Arthur Conan Doyle, Mary died without a word regarding her cause of death.

But series co-creator Mark Gatiss did not provide a straight answer regarding the fate of Mary next season during an interview with Radio Times.

"You can always expect tragedy as well as adventure, that's just how it goes," the series co-creator said. "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 – we've introduced Sherlock and Mycroft's parents [for instance], I don't think they've ever been seen in any adaptation – so there are lots of surprises to come."

"Sherlock" season 4 is expected to premiere in spring 2017.