BBC Sherlock
Benedict Cumberbatch and Martin Freeman during a promotional shoot for 'Sherlock' season 4. bbc.co.uk

It appears that BBC's spectacular series 'Sherlock' has ended, for now. The detective series adapted from Sir Arthur Conan Doyle's work reached a sort of conclusion in season 4's 'The Final Problem' episode. Though it wraps itself nicely without any cliffhanger, the showrunners hint it's not the last we are seeing of Benedict Cumberbatch and Martin Freeman as Sherlock Holmes and John Watson.

Speaking to RadioTimes, the writers of 'Sherlock,' Mark Gatiss and Steven Moffat said that events at the end of The Final Problem could be just the beginning of a new set of adventures and an eventual fifth season. "The reason we [ended with] Rathbone Place is that, actually, if we do come back – and we would love to come back – we could absolutely very easily start with a knock at the door and Sherlock saying to John 'Do you want to come out and play?'. They have become the two heroes that we always knew them to be," said Gatiss, who also plays Sherlock's elder brother Mycroft Holmes in the BBC series.

Gatiss also added that the intention of his and of Steven Moffat was to do an original story of Sherlock Holmes and Watson so that the audience could also grow with them and be more invested than if they were faultless experienced crime solvers. "Our original intention of the series was to go back to the beginning and see them as younger men and... restore it to its factory settings. But I think what's actually happened is that we have now done the story of how the Sherlock Homes and Doctor Watson that we have always known, how they became those men. It's actually really a backstory," Gatiss said.

Steven Moffat added that Sherlock has experienced that growth in the series, not a growth in intellect, which he has plenty already, but an emotional growth; an ability to connect and deal with humans, which he lacked initially. He was treating others as clinical subjects or forensic evidence. This has happened not just due to Mary's (Amanda Abbington) death, but also due to the sudden appearance of his sister Eurus.

"He sees that, partly because the extreme of [his sister] Eurus who has no connection to anything, is just pure brain, not understanding anything about what it is to be human. [This] makes him realise everything he has worked towards, everything he has tried to get away from himself and deny about himself, is what makes him the strongest," Moffat said, adding that though Sherlock isn't as smart as Mycroft or his sister, he now understands human beings and their emotions which the others fail at. Sherlock, as a result, will be a much stronger sleuth in season 5, if and when it goes into production.

Moffat adds, interestingly, that Sherlock's newfound wisdom about humanity would go on to transform him into the Sherlock Holmes we know and love; one played by actors Basil Rathbone and then Jeremy Brett; 'the wise old man... who is still terrifying and still cold but has a heart that you never doubt.'

However, it is still too early to give the green signal, as both Benedict Cumberbatch and Martin Freeman will be busy with their film projects, especially their contract at Marvel Studios. So, series 4 might just be the end of it. "If this was the last time – we're not planning it, but it might be, it's possible – we could end it there. We couldn't have ended it on any of the previous series because they always ended up with whopping great cliffhangers."

Moffat also told Radiotimes.com that they thought about putting a card at the end of 'The Final Problem' that said "The Beginning" but then decided that it would be "too cheesy." So the prospect of a new beginning is there, in the minds of the writers, waiting for a right time in the near future to hatch.

As for the stories that might inspire the three episodes of season 5, Moffat had earlier told Vulture, that Mark Gatiss has a desire to adapt Doyle's Sherlock Holmes short story, 'The Red-Headed League.' He revealed that he's interested in 'The Engineer's Thumb' and the Irene Adler element from 'The Greek Interpreter' where he'd like to explore the option of having Adler and Holmes meet again. However, at the moment, everything hangs in the air until further announcements.