• "Sherlock" Season 4 is set to return on December.

"Sherlock" Season 4 is set to return on December. (Photo : YouTube/DetectiveHolmes)

"Sherlock" Season 4 is underway, and the showrunners hinted that this year's story will be life changing for Sherlock, John Watson, Mary and the other season regulars. Co-creator Mark Gatiss already revealed that one of the prominent villains in "Sherlock" may make a return this season.

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According to Gatiss, the cast and crew completed filming Block 1 for "Sherlock" Season 4; however, they may take a short break before they continue filming. Although it was reported that the show has been booked for a 2017 release, Martin Freeman said otherwise. According to The Independent, the actor, who plays Dr. John Watson in the series, stated that the show will return to TV this December, which is the usual release date for the previous "Sherlock" seasons.

The upcoming "Sherlock" Season 4 marks the impending comeback of Jim Moriarty, portrayed on screen by Andrew Scott. The return of Moriarty was hinted in "Sherlock" Season 3 finale, when his mug was flashed with a one-liner that read, "Miss me?"

"Ghosts of the past are rising in the lives of Sherlock Holmes and John Watson bringing adventure, romance and terror in their wake," Gatiss teased. Perhaps the "ghost" he was referring to was Moriarty.

Gatiss also hinted that Moriarty's return will spell big trouble for Sherlock, and will deal heavy repercussions that will have far-reaching effects.

Meanwhile, John Watson and his wife Mary opens a new chapter in their lives in "Sherlock" Season 4 as they enter parenthood. Actress Amanda Abbington, who plays Mary, revealed that the first-time parents would probably be reckless as parents, but assured that the kid will not be bullied around since the child will have an assassin mother and an army doctor father by his or her side.

"I can't wait for everyone to see season four. But you will have to wait... though not for long... And it will be worth it," actor Benedict Cumberbatch teased about "Sherlock" Season 4, as quoted by Daily Mail.

Fans of "Sherlock" have missed the show terribly, having gone off air for two years. The last time they saw the witty detective was on the New Year's Day "Sherlock" special, titled "The Abominable Bride." That episode gathered 11.6 million viewers, the highest number of audiences in "Sherlock's" entire run.

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