The fourth season of BBC's hit series "Sherlock" is expected to air sometime in 2017, and when the series finally appears, fans may have to ready themselves to bid Mary Watson (Amanda Abbington) farewell.

The upcoming season of "Sherlock" is rumored to be emotionally draining, and main characters will be stricken with tragedy. During Comic-Con, which took place in July, co-creator Steven Moffat said, "We know very, very clearly what stories we're doing. Where each episode goes, what the shattering, emotionally draining, you'll never be the same again and you'll never stop crying cliffhangers will be."

The death of John's wife, Mary, occurred during an unspecified point between the stories "The Final Problem" and "The Adventure of the Empty House," and was touched upon in later Arthur Conan Doyle stories. Her death happened shortly after marrying John, leaving him a widower. Mary Freeman, who portrays John, stated he wouldn't be surprised if Mary did die during the series.

Freeman told Telegraph, "While we play fast and loose with the original stories, we generally follow the trajectory of what Conan Doyle did. So John gets married, and then Mary dies -- so at some point presumably she'll die."

The "Sherlock" special episode scheduled to air Christmas of 2015 is expected to tide over fans until the arrival of the fourth season. The special will show Benedict Cumberbatch's Sherlock as "nicer," less like his "usual sarcastic self," and he will be "a proper polished Victorian gentleman," Moffat said.

Eager fans can also look forward to an incredible evening at to the Regent Theatre on Monday, Nov. 23, "Sherlock: From Script to Screen." For the first time, Gatiss (who also plays Sherlock's brother), Moffat and series producer Sue Vertue will share insights into the conception of the show and an understanding of how the plots and characters are developed.

"We're very excited to be bringing the magic of the show to Australia and meeting Sherlock fans over there," Vertue said.

"Sherlock: From Script to Screen" will occur after the Doctor Who Festival held in Sydney two days before. Fans of "Sherlock" and "Doctor Who" who will be in Sydney can expect excitement.

While the upcoming season will be darker and more intense, the show will continue to have sharp turns, such as Mary being an assassin or the fake death of Sherlock.