The 'Sherlock' Season 4 trailer is here

"Something's coming..."

That's what Benedict Cumberbatch's Sherlock Holmes says in the new trailer for Season 4 of Sherlock, which was unveiled Sunday at Comic-Con.

Another ominous-sounding line from the clip: "The roads we walk have demons beneath, and yours have been waiting for a very long time."

It might be a long time before fans learn what that quote is all about: New episodes don't debut on Masterpiece on PBS until 2017.

Not all of the cast could make the show's Comic-Con panel in San Diego this weekend, so they shared this video.