It's definite that "Sherlock" Season 4 will come back in 2016, and finally some mysteries will have their answers revealed in the new season.

There's the belief that another Holmes brother will be part of the show. Holmes has two other brothers. One is Mycroft Holmes, played by Mark Gatiss, who works for the British government. Sherrinford Holmes has been mentioned but has not yet been shown. Many believe that he will be in Season 4, but the question is, Who will play his part? This brother, who is the eldest in the brood, is the manager of the Holmes estate. A favorite to play the part is Tom Hiddleston, according to Hallels.

As for the female cast, it is definite that viewers will be seeing Mrs. Hudson, played by Una Stubbs. She is the landlady of Holmes and Watson and his wife, Mary Morstan, who was a former assassin. It had been teased that one of the ladies will die, although the identity of who it might be has not yet been discovered. Amanda Abbington, who plays the part of Mary in the drama, assured fans that Mary will be in Season 4. The question now is, For how long she will be in the show?

Mary was carrying Watson's baby in the previous season. There is a rumor that the baby will be introduced in the new season. Other characters that are returning are Janine (played by Yasmine Akram), Molly Hooper (played by Louise Brealey) and Irene Adler (played by Lara Pulver).

Martin Freeman, who plays the role of Dr. John Watson, revealed during an interview that there will be a special episode of "Sherlock" that will be shown before the premiere of the new season.