'Sherlock' co-creator says 'tragedy' to come in season four LONDON, Nov. 21 (UPI) -- Sherlock fans should prepare themselves for tragedy in season four. Co-creator Mark Gatiss, 48, said as much in an interview Thursday with Radio Times. Many fans expect Dr. John Watson's (Martin Freeman) wife, Mary Morstan (Amanda Abbington), to die in accordance with Sir Arthur Conan Doyle's Sherlock Holmes novels, but Gatiss said the sad events may manifest themselves differently. "You can always expect tragedy as well as adventure, that's just how it goes," he told the publication. 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. "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," he elaborated. We've introduced Sherlock and Mycroft's parents [for instance], I don't think they've ever been seen in any adaptation -- so there lots of surprises to come. Sherlock debuted on BBC One in 2010, and will return for a fourth season in 2015. The series takes a contemporary spin on Doyle's series of books, and stars Benedict Cumberbatch as Sherlock Holmes, Rupert Graves as Detective Inspector Greg Lestrade, Andrew Scott as Jim Moriarty and Louise Brealey as Molly Hooper.