BBC's detective drama "Sherlock" has enjoyed a successful run in all the three seasons and though no official date has been announced for Season 4, stories and rumors are floating far and wide.

While it is still not confirmed if the secrets and mysteries of the series will be disclosed in the next season, speculations are rife about a changed Holmes (Benedict Cumberbatch) in Season 4, reports claim. Also, the investigator will have a secret plan in his armor to counter the approaching troubles as they are quite different than what he has encountered before.

The next installment of  "Sherlock" will follow the previous season's flavor with the detective and his assistant Doctor John coming across unexpected challenged. However, this time, the stakes will be higher. Rumors are doing the rounds about the next season being darker and more intense than what we have seen in the previous editions.

Notably, actor Cumberbatch had also said at the recently-concluded San Diego Comic-Con that the series will be myopically dark. He referred to it in an indirect way, jokingly saying that the talks about the end of the universe darkness can wait, one should see it in present as it is in front of all.

It is being said that Holmes will come back to London after the forced exile and again team up with Doctor Watson. However, his enemies are waiting. Professor Jim Moriarty is certainly there as actor Andrew Scott, who plays the professor, has confirmed his presence in the next season of "Sherlock" as the professor but there is more. It is said that a new villain is also lurking somewhere in the city.

According to reports, Toby Jones has been roped in to play the role of this unnamed villain.  Showrunner Steven Moffat has also said that he will be the darkest villain of the show and warned the audiences about his viciousness, saying that viewers will find him horrific as soon as he appears in the next season.

Well, this certainly makes for exciting news as the drama and thrill will also be commensurate with the villains and the darkness.