'Sherlock' Season 4 News & Plot Spoilers: New Episode Set in Victorian Era! Is Moriarty Coming?

Benedict Cumberbatch and Martin Freeman are already shooting for the fourth season of BBC's hit series, "Sherlock," and fans are squirming with excitement.

However, before the fourth season airs next year, the duo are heading to Victorian London for the special, show creator Steven Moffat confirmed via The Independent.

Moffat also spoke to Entertainment Weekly at the South by South West Festival, telling the news source, "We wouldn't have done the story we're doing, and the way we're doing it, if we didn't have this special."

It's a standalone special and not part of the fourth season. Moffat cleared it up, saying, "It's not part of the run of three episodes. So we had this to do it - as we could hardly conceal - it's Victorian. [Co-creator] Mark Gatiss and me, we wanted to do this, but it had to be a special, it had to be a separate entity. It's kind of in its own little bubble."

After photos of Cumberbatch and Freeman were released last year in their Victorian costumes, this news hardly comes as a surprise for fans. However, it has been noted that filming for the special episode has already wrapped up, and Moffat is said to be "very pleased" with the final outcome.

But why go back to the Victorian era? According to the International Business Times, fans already have different theories: There's a cold case in that era (as Sherlock is known to picture himself in different situations), a wormhole (although that will make it more sci-fi than mystery) brought them there, drugs may be involved, or they were transported there with help from the TARDIS (as Moffat is also showrunner for "Doctor Who" and fans have been clamoring for a crossover).

One thing is definitely sure, though: Jim Moriarty, Sherlock's nemesis and a fan-favorite villain, is not returning, especially when a BBC executive producer made it clear that it will be impossible to bring Andrew Scott's character back considering that he shot himself in the face. If ever he will make an appearance, it will be through flashbacks or time-travel, the latter, as Christian Today noted, being highly unlikely.

It's not easy being a Sherlock fan with all the waiting you have to do. But, with its A-grade storytelling, you can bet it's worth the wait.

Filming for the fourth season is currently ongoing; however an air date has not been set for the special (although this could be the Christmas special that would air in December). Season four will premiere sometime in 2016.

Check out this fan-made trailer: