"Sherlock" co-creator Mark Gatiss has some bad news for fans of the show, telling them to "expect tragedy" during the upcoming fourth season of the hit BBC drama.

In an interview with the Radio Times, Gatiss, who also stars as Mycroft Holmes in the show, said, "you can always expect tragedy as well as adventure, that's just how it goes." Although he refused to say whether that meant the death of John Watson's wife Mary which is what takes place in Arthur Conan Doyle's original, "Sherlock Holmes" tales.

The show, which stars the guy who seems to be everywhere these days, Benedict Cumberbatch in the title role and "The Hobbit's" Martin Freeman as Watson, has Freeman's wife in his regular life Amanda Abbington star as Mary Watson. Freeman himself has speculated before that Mary would likely meet her end, telling the Daily Telegraph, "while we play fast and loose with the original stories, we generally follow the trajectory of what Conan Doyle did... so [John] gets married, and then Mary dies.  So at some point presumably she'll die."

Gatiss also stated that fans shouldn't necessarily assume that is what is going to happen. "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 said.

A one-time "special" episode of "Sherlock" begins production in January 2015, to be shown at the end of the year, with the three-episode, fourth season to shoot later in 2015 and air sometime in 2016.