Sherlock fans can expect some tear-jerking moments along with the deductive drama when the show finally returns for series four, warns co-creator Mark Gatiss.
“You can always expect tragedy as well as adventure, that’s just how it goes," he tells RadioTimes.com.
But Gatiss won't be drawn on whether that tragedy will include the death of John Watson's wife Mary, played by Martin Freeman's real-life partner Amanda Abbington.
Freeman himself has suggested she'll be killed off "at some point”, because that's what happens in Sir Arthur Conan Doyle's Sherlock Holmes stories.
“While we play fast and loose with the original stories, we generally follow the trajectory of what Conan Doyle did," Freeman told The Telegraph earlier this year. “So [John] gets married, and then Mary dies – so at some point presumably she’ll die.”
But Gatiss says viewers should assume nothing.
"Just because it’s in the stories doesn’t mean it’ll happen in the series because there’s an awful lot of changes and an awful lot of places to go and things to do," he says.
"It should be clear by now that while, of course, Doyle is our absolute god, we have gone quite a long way away as well – we’ve introduced Sherlock and Mycroft’s parents [for instance], I don’t think they’ve ever been seen in any adaptation – so there are lots of surprises to come.”
It's true that Gatiss and co-creator Steven Moffat have so far taken a pick-and-mix approach to dramatising the Sherlock Holmes adventures, putting together elements from a variety of Doyle's stories and adding their own twists and flourishes.
But what Freeman says is also true – they've tended to follow the basic road map laid out by Doyle – and the actor has been right before when letting things slip. He told us a long time ahead of the official announcement that the next episode of Sherlock would be a one-off special and I suspect he'll be proved right that it's a Christmas one too.
Either way, Abbington’s character has already outlived her literary counterpart. In the original stories, Mary Morstan dies sometime during the period between Holmes's apparent demise at the Reichenbach Falls and his return three years later, both of which have already taken place in Sherlock.
But while we assume the 19th-century Mary died of natural causes (her death is only briefly touched on in the books) Abbington's kick-ass former assassin is likely to meet her end in a more spectacular way.
And if and when that happens, there's one bright side for fans... the original stories see Dr Watson and Sherlock Holmes back where they belong following Mary's death – living together again in their Baker Street flat.
Mark Gatiss supports the London Lesbian and Gay Switchboard, which is celebrating its 40th anniversary this year