Sherlock writer Steven Moffat has teased that the upcoming series four will be much darker, and will include a big reveal that has so far gone over the heads of fans.

The BBC series, starring Benedict Cumberbatch and Martin Freeman as Sherlock Holmes and John Watson, is known for baffling viewers with seemingly unanswerable questions and then providing completely unpredictable solutions, but Steven told Entertainment Weekly that one such question had not even been spotted yet.

He said of series four, which has not yet been written: “There are answers coming to questions which nobody has asked. There’s one thing that no one has really brought up.

Steven Moffat and Mark Gatiss



Steven Moffat and Mark Gatiss (Ian West/PA)

 

“I think [co-creator Mark Gatiss] and me, we’re very exultant about a little thing we’ve set up that no one is talking about. It’s not that we’re being clever. We never know. Sometimes people go mad for one thing we think is quite trivial and completely ignore something we think is standing right in front of you.”

He added: “The first series was all about the beginning of their friendship. Second about the formative stages, the love and fear and loss and all that. The third was good days, me and my pal and my pal’s wife. Those are golden days.

“The missing element in a lot of Sherlock Holmes adaptations is allowing it to be funny. There’s a lot of humour in Sherlock Holmes, and it’s ignored in a lot of adaptations. [Series four] is going to be consequences. Chickens come to roost.

“It’s dark in some ways — obviously it’s great fun and a Sherlock Holmes romp and all that — but there’s a sense of things coming back to bite you. It’s not a safe, sensible way to live. It’s hilarious and exhilarating some days, but some days it’s going to be bloody frightening.”

Martin Freeman and Benedict Cumberbatch in Sherlock



Martin Freeman and Benedict Cumberbatch star in Sherlock (BBC)

 

Asked how it would make fans feel, Steven said: “Desperate for series five. We’re certainly going to put them through the mill. It’s going to be more of an emotional upheaval. Hopefully enjoyable and fun, all the things Sherlock must always be. It will be tough at times. Maybe that’s the word? A tougher series.”

Steven also explained how he managed to keep Benedict and Martin with the show, despite their success in Hollywood.

He said: “The reason we still have Benedict and Martin is we still give them acting challenges. Otherwise they wouldn’t come and play with us. They don’t need the money. What we give them in terms of money isn’t something they’d regard as a significant fee any more.

Benedict Cumberbatch and Martin Freeman



Benedict Cumberbatch and Martin Freeman (Ian West/PA)

 

“We’re making this in a shed in Wales. We think really carefully about giving them something to play because they’re both amazing actors.

“[Fans] get very cross that we don’t make more. Had we made this as a conventional series it would be over. Because Benedict and Martin are never going to agree for the rest of their lives to do any series for runs of six or 12. They don’t need the money and they want a bigger variety of jobs.”

He continued: “The only version of Sherlock you’re going to get is this one. I think that’s a pretty good deal. Compare us to Guy Richie’s Sherlock Holmes: we’ve made 10, he’s made two. Or how often you get a James Bond film. You’ll get a longer-lasting, richer experience the way we’re making it.”