The waiting game for the fourth season of "Sherlock" continues, as the cast and crew of BBC's crime drama have yet to begin filming for the next three episodes of the series.  

Series co-creator Steven Moffat earlier announced that the filming for "Sherlock" season 4 will begin in spring 2016, which means that the next season will be aired sometime in 2017. That only shows that fans have to wait for at least two years in order to see a fresh episode of the TV adaptation of Sir Arthur Conan Doyle's "Sherlock Holmes" detective novels. 

But what should the viewers expect when the series airs its fourth season? 

Moffat previously said that the theme for "Sherlock's" upcoming season is about consequences. It could mean that the show will stay true to the stories in Conan Doyle's book wherein John Watson (Martin Freeman) marries Mary Morstan (Amanda Abbington), only to become a widower later on. 

Freeman confirmed this plot in his past interview with The Telegraph UK, saying: "So [Watson] gets married, and then Mary dies - so at some point presumably she'll die." 

But while Watson and Mary's fate in season 4 seems to have been revealed, little is known about his friend Sherlock Holmes (Benedict Cumberbatch) and Irene Adler (Lara Pulver), who had some sort of connection in the past seasons. 

Movie Pilot noted that fans would like to see Adler back in "Sherlock" season 4 since she made quite an effect on the detective when she appeared in the series. Fans reportedly want to see if Sherlock will finally give in to his attraction to Adler. However, Moffat's co-creator Mark Gatiss seemed to be unsure if bringing her back in the series will be a good idea.

At this point, fans are still waiting to hear more revelations from the series creators regarding the direction of "Sherlock" in season 4.