Fans caught their first glimpse of "Sherlock" season 4's new antagonist, Toby Jones, in the new trailer unveiled for the upcoming series at the San Diego Comic-Con 2016.

Toby Jones' identity in the series has not yet been officially confirmed, but a line on his online Spotlight CV seems to suggest that he will play a man named Culverton Smith. It also implies that the "Sherlock" season 4 will serve as a reinterpretation of "The Dying Detective" by Sir Arthur Conan Doyle.

The footage also hints at the possible return of Moriarty, who is shown right at the opening of the trailer saying the words, "Miss me?" in what appears to be a video clip.

Benedict Cumberbatch's Sherlock appears somewhat wearier, colder and unhappier in the trailer video than usual, and the reason for that remains to be seen. The video also features Martin Freeman's Watson, Louise Brealey's Molly Hooper and Rupert Graves' Lestrade.

Moreover, the trailer reveals a quick confrontation scene between Una Stubbs' Mrs. Hudson and Mark Gatiss' Mycroft, the brother of Sherlock.

"Get out of my house, you reptile," says Mrs. Hudson to Mycroft in the video.

Generally, the trailer makes it looks like the upcoming season will be home to different kinds of explosive revelations and personal ruins not only for Sherlock but for his allies as well.

At the Comic-Con, Benedict, Abbington and Gatis all agreed that "Sherlock" season 4 is going to be the darkest season the showrunners have written for the show since it debuted in 2014.

"A real emotional rollercoaster," said Cumberbatch.

"Sherlock" season 4 returns sometime in 2017 on BBC.