Whether you caught the full series of 'Sherlock' season 3 upon its U.K. airing weeks ago, or the PBS airing of finale installment "His Last Vow" last night, there can be no denying that the Benedict Cumberbatch-Martin Freeman drama left us on one of its most shocking cliffhangers to date. Apart from our collective "whuh-huh?" reactions, find out what series boss Steven Moffat had to say about the surprise character return, and what it means for 'Sherlock' season 4 (and 5)!

You're warned of every spoiler under the sun for the first three seasons of 'Sherlock' from this point on, as last night's finale gave us one major twist in its final moments: Moriarty is back! Yes, in spite of his apparent suicide at the climax of season 2 finale "The Reichenbach Fall," the final moments of "His Last Vow" saw the villain commandeering every screen in the greater London area to ask "did you miss me?"

Of course, while we don't yet know when 'Sherlock' season 4 will film or premiere, given its cast and crew's increasingly busy schedule, showrunner Steven Moffat assures viewers that the twist of Moriarty's return will have heavy implications for future seasons, and wasn't devise for a cheap shock. So, while Moffat can't quite atone for previous claims that Moriarty and Sherlock would have been absurd to "throw fake suicides at each other," Moffat talked to TVGuide about the extensive plans surrounding Moriarty's return next season:

We always knew what we were going to do with Moriarty. This has been the game plan since the end of Series 1 when we realized we had a crack on our hands with Andrew [Scott]. This is something that the whole series has been building to. I won't say what it is we're doing, but we have plans. And I'm pretty bloody certain those plans will please people...

We had a whole set of specific story ideas mostly for Series 4 but reaching into Series 5, which is because Mark [Gattis] and I happened to be chatting one day and as occasionally happens, we just ducked out of the rain and into the accountant's office. We found ourselves getting very animated about a set of ideas we could have. I think they're the best set of ideas we've ever had for Sherlock. So I'm very excited about that.

Moffat also assured that the fourth season would likely pick up with little to no time lag, wanting to account for everything they'd done from the moment of the big reveal. "There will be nothing left dangling," says the creator.

We have our own ideas about Moriarty's return, but what say you? Is it a comfort to know that the villain's return had been planned early on, or would you want the fourth and fifth seasons to concentrate on new villains as with Lars Mikkelsen's Charles Augustus Magnussen? Check out the shocking return below, and give us your 'Sherlock's eason 4 predictions in the coments!

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