'Sherlock' season 4 spoilers, plot news: First teaser reveals disheveled-looking Sherlock Holmes, Moriarty set to return?

"Sherlock" season 4 is probably one of the most-awaited shows to premiere next year, and the recently-concluded Comic-Con event gave fans a glimpse of what's in store for the hit BBC series.
A new trailer for the upcoming season has been released and it seems that more troubles are coming Sherlock (Benedict Cumberbatch) and John's (Martin Freeman) way. The short teaser opens with the presumed-to-be-dead Moriarty (Andrew Scott) saying: "Did you miss me?" He might return at some point in the story, but it remains to be seen how he will be able to do so. "Something's coming," the voiceover warns, clearly referring to a huge problem which the duo will have to deal with.
Veteran actor Toby Jones has been confirmed as the new villain and his evil laugh in the teaser serves as a preview of how menacing his character is. Sherlock appears to be sporting a scruffy look which is a complete opposite of his clean-shaven face viewers are used to seeing. Mycroft (Mark Gatiss) can be heard in the background stating: "The roads we walk have demons beneath, and yours have been waiting for a very long time." This might be in connection with Sherlock being admitted to a hospital after footages of nurses walking across a hallway. Aside from the explosions and gun battles, Mrs. Hudson (Una Stubbs) is seen being involved in a conflict with Mycroft while angrily telling him: "Get out of my house, you reptile."
Despite earning a couple of Emmy nominations this year, there may be a possibility that this will be Cumberbatch's last season according to CNN. Since he is an A-list movie actor and his stint in the small screen cannot be guaranteed to go on for a longer time, an end may already be in sight for Sherlock or the whole show.
In an interview with The Telegraph, executive producer and co-creator Steven Moffat expressed how he still can't believe that the show was able to have high-profile stars like Cumberbatch and Freeman. "I don't know how long we can keep it going," Moffat said. "I'm personally willing but I'm hardly the main draw."
If the stars will no longer be available for another season, Moffat says he would still be open to a comeback sometime in the future. "That's why I think it's unlikely that we've completely finished it," he continued. "There would be nothing strange in stopping for a while. It could go on forever, coming back now and again."