"Sherlock," Season 4 ranks high on the viewing list of detective show aficionados across the world. Though viewers will have to wait until next year to feast on the intriguing drama, they can be sure that the drama is going to be full of mystery and suspense.

 "Sherlock" Season 4 is slated to be the darkest season of the show as it is going to tell stories with a dark side and that too with relation to each character, reports The Christian Post. It is also going to be tough on the detective and his friend Dr. John Watson. This is because Mary is back in town with her evil old tricks and looking to make life difficult for the two friends. She will betray them and as fans know, she is an assassin, who has been after Sherlock all this while.

To make things worse for the friends, Moriarty will also be back and if this was not enough, the third Holmes brother Sherrinford is coming as well. The former will bring along with him a lot of darkness. However, Sherlock will challenge him and knows well that he is up to something malicious. As for Sherrinford, the character is likely to be played by Tom Hiddleston and he will be seen as a ghost as well. This ghost will haunt Holmes a good deal in Season 4.

Speculations suggest that "Sherlock" Season 4 will have some backstories in the course of its progression. A time lapse is also in the wings and the two main characters will undergo this "time lapse" in order to solve mysteries. Last but not the least, there will also be fights between Sherlock and the new villain Culverton Smith (played by Toby Jones), who is said to be the darkest villain the series has seen.

In other reports the Netflix release date of "Sherlock" Season 4 has been also revealed, claims Game & Guide. According to the site Netflix Life, fans can get to see the fourth season via the live streaming service in June or July 2017. This speculation is based on the release dates of the previous seasons.