"Sherlock" season 4 will be a culmination of many things. This is what show creator, executive producer, writer, and actor Mark Gatiss described the next season of the series while speaking at the Victoria & Albert Museum.

"There are things that come to fruition in this series which we've been planning for years," Gatiss, who also plays the role of Sherlock's (Benedict Cumberbatch) brother, Mycroft, revealed, as quoted by Radio Times.

He did not elaborate on this clue, though, so fans might have to do the digging themselves as they wait for the revelation in "Sherlock" season 4.

On the other hand, Gatiss also opened up about the passion of "Sherlock" fans to uncover the mysteries of the show but pointed out that they should look harder.

"People also find things that aren't there, which is my favorite. And then miss the blindingly obvious things that are there. People read an awful lot into it," he went on to say.

It is looking like "Sherlock" season 4 will again be laden with secrets, but the word of warning by Gatiss might help fans discover what the show is hiding.

He did suggest that fans keep it simple, emphasizing that the series is for the "casual viewer," which means he would not complicate it by tying the series into a whole other mythology.

One of the expectations in "Sherlock" season 4 is that James Moriarty (Andrew Scott) will be revealed alive after all these years. In the season 2 finale, fans will remember that Sherlock's rival killed himself.

Many believe that he faked his death, a card that Sherlock already played. The references to him in the "Sherlock" season 4 trailer and the season 3 finale had many thinking twice if Moriarty really committed suicide.

Being an individual with the wits that can match that of Sherlock, Moriarty is someone who fans would imagine will not give up without a fight and someone who always has tricks up his sleeves. It remains to be seen whether Moriarty will return or not.

Dubbed as the darkest season yet, "Sherlock" season 4 premieres early next year.