Sherlock season 4 first trailer

Sherlock season 4 looks dark and action packed based on the first trailer from PBS Masterpiece.

Below we see glimpses of car chases, a tease of Moriarty actor Andrew Scott (yes, we missed him), and a tearful, traumatized-looking Holmes (Benedict Cumberbatch).

“Everyone they know is under threat,” we’re warned, with Mycroft (Mark Gatiss) noting to Sherlock: “The roads we walk have demons beneath, and yours have been waiting for a very long time…”

The trailer confirms the new season will debut in 2017. Perhaps most ominously: Benedict Cumberbatch’s Doctor Strange goatee has come to Baker Street.

Also: What’s with the creepy nurses?

“It’s no spoiler: We explicitly said it is the darkest season yet and still obviously full of laughs and fun, but is generally tonally dark,” Gatiss, who is also the show’s co-creator, told EW at Comic-Con this weekend.

For more details on Sherlock, including what went down at the show’s Comic-Con panel on Sunday, head here.

Entertainment Weekly is on the scene at San Diego Comic-Con. Go inside with all our coverage, available here.