Los Angeles, Jul 25 (IANS): Fans of the Emmy-winning TV series "Sherlock" have a reason to rejoice, as a new trailer for the fourth season of the show is here with a promise that "everything they know will be tested".

Fans at the British mystery show�s Comic-Con panel were treated to the first trailer for the fourth series here. Stars Benedict Cumberbatch and Amanda Abbington, co-creators Steven Moffat and Mark Gatiss and producer Sue Vertue were present.

The new look seemed to be more action-filled than past instalments, and intoned that �Something�s coming. Maybe it�s Moriarty, maybe it�s not. But something�s coming", reports variety.com.

Cumberbatch returns as Detective Sherlock Holmes, joined by his best friend Dr. John Watson, played by Martin Freeman.

The show last left off with Andrew Scott�s villainous Moriarty seemingly coming back to life after shooting himself in the face.

Holmes, however, figured out in the 2016 Christmas special, �The Abominable Bride�, that Moriarty is in fact dead -- but that doesn�t mean that the criminal mastermind doesn�t pose a threat.

Complicating matters is the fact that Toby Jones will be joining the show as another one of Arthur Conan Doyle�s villains. Holmes and Watson will have to face problems with both bad guys, which, as the new trailer shows, will be a challenging feat even for them.

�Sherlock� will return to the BBC in 2017, and will likely air in the US shortly afterwards.