"Sherlock" fans welcomed the new year with the premiere of the BBC show's fourth season. And while the shocking first episode may indicate what the rest of the season has to offer, nobody knows what season 5 will bring — including creators Steven Moffat and Mark Gatiss.

It has been highly rumored that season 4 may be the final installment in the immensely popular and acclaimed detective series. Moffat and Gatiss have both spoken out on the possibility of a fifth season, and star Benedict Cumberbatch hasn't exactly remained mum either. It has been said that the biggest challenge in arranging a fifth season would be coming up with the right schedule because of other commitments. But everyone involved seems to be up for another round, if given the chance.

If the stars aligned for everyone, what would the fifth season look like? According to Moffat and Gatiss, pretty much unknown. 

"We've had the most sketchy discussions on what we'd do," Moffat told Newsweek. "We have an idea for season five on a Post-it note. That's as far as we've got. Unless I'm lying?" Gatiss, who also plays Mycroft Holmes on the series, added.

The co-creators also talked about the possibility of moving to a new network or streaming service, explaining that there wouldn't even be a chance. 

"I can't see it. I'd be against that. It's been a BBC show, they supported it in the first place," Moffat explained. "If Benedict or Martin or any of us were that greedy we'd already not be doing the show. We've all had better offers."

The premiere episode of "Sherlock" season 4, titled "The Six Thatchers," saw Sherlock and John (Martin Freeman) solving a case involving shattered busts of Margaret Thatcher and the secret past life of Mary Watson (Amanda Abbington). But it was the ending that shocked most fans who tuned in, when Mary jumped in front of a bullet for Sherlock.

"Sherlock" season 4 airs Sundays at 9/8c on PBS/Masterpiece.