“A real emotional roller coaster… with jokes.”

The Sherlock Series 4 Comic-Con panel has taken place today in San Diego with the stars and writers of the show teasing information and revealing a new teaser trailer.

The BBC One trailer opens with the appearance of Andrew Scott as Moriarty, Sherlock‘s nemesis who shot himself at the end of series 1. The question is, is he real or once again in Sherlock‘s mind?

We also get a look at Toby Jones playing an undisclosed character – the only information being he is a playing a villain. Other cast featured include Martin Freeman, Mark Gatiss, Una Stubbs, Rupert Graves and Amanda Abbington.

Asked during the Comic-Con panel to describe series 4, the cast said to expect its darkest series yet, with star Benedict Cumberbatch saying it’s “a real emotional roller coaster,” with actor and co-writer Gatiss quick to add, “with jokes.”

Gatiss and writer Steven Moffatt chose to describe the series with three names: “Thatcher, Smith and Sherrinford.”

The writers also revealed that series 4 may not be the last but with the main stars being so busy with other projects it’s difficult – but there may be more series.

Sherlock Series 4 will air on BBC One in 2017.

Watch the teaser below…