‘Sherlock’ Season 4 Air Date, News Update: Benedict Cumberbatch Series To Reveal Moriarty, Mary Watson In Cahoots?

"Sherlock Season 4" has betrayal for Holmes (Benedict Cumberbatch) waiting in the wings and it may have to do with James Moriarty (Andrew Scott) and Mary Watson (Amanda Abbington). While "Sherlock Season 3" confirmed that James Moriarty is dead, fans of the BBC series are expecting a surprise twist from Holmes' nemesis.

Digital Spy cites "Sherlock" series fan theories, which includes the friend of Sherlock Holmes and wife of John Watson (Martin Freeman) - Mary - being a double agent for James Moriarty. "Sherlock Season 2" revealed Mary to be an assassin right before she shot Holmes.

Wonderful news to wake up to. Congratulations to team #Sherlock on our #Emmy win!

— Mark Gatiss (@Markgatiss) 19 September 2016

Although Mary Watson seemed to have come a long way from "Sherlock Season 2," with Holmes and John Watson forgiving her transgression, S4 may reveal that the darkness still lurks within. Certainly, while co-creators and co-writers Steven Moffat and Mark Gatiss (Mycroft Holmes) along with the BBC series cast assuring that "Sherlock Season 4" will have excitement and laughter in its pages, so will tragedy.

The Abominable Bride won an #Emmy for Outstanding Television Movie. Congratulations to everyone involved. #Sherlock pic.twitter.com/kf6rWd63jB — Sherlock (@Sherlock221B) 19 September 2016

According to Digital Spy, "Sherlock" series fan theory highlights that Mary Watson may not simply be running from her past. Instead "Sherlock Season 4" may reveal that Mary Watson may actually be acting on behalf of James Moriarty.

Congrats to @CHIMPSINSOCKS who has won an @EW Poppy Award for best supporting actress in a limited series/TV movie! pic.twitter.com/GMMjDKuSrm

— Sherlock (@Sherlock221B) 13 September 2016

Parent Herald cites Amanda Abbington in revealing that Mary Watson will be up to her old tricks in "Sherlock Season 4." Whether Mary Watson turns spy once again for or against Sherlock Holmes and Martin Freeman will be revealed soon enough.

A separate Parent Herald report cites OK in labeling "Sherlock Season 4" as the most twisted run for the BBC series. Certainly, Benedict Cumberbatch, Martin Freeman, Mark Gatiss and Steven Moffat unanimously indicated that "Sherlock Season 4" will be the darkest season for Holmes and John Watson.

The BBC is expected to air "Sherlock Season 4" in January 2017. Do you believe Mary Watson will die in "Sherlock Season 4" from being a double agent or do you think she will do a heroic turn for Holmes and John Watson against James Moriarty?