At first,Sherlockseason 4 started with the gang happier than ever.
Below we speak to showrunner Steven Moffat about the major death and how it changesSherlockmoving forward.
What made you decide to get rid of Mary?

Credit: PBS
They had fun making it a trio but it doesnt work long term.
Mary was always going to go and we were always going to get back to the two blokes.
Thats how the show works and always will.
We reset to the most traditional and famous version of the format.
I like your use of the death fable early on and aquarium water youd overlay into a few shots.
There was also the black sharks that comprised Baby Watsons mobile.
We knew where we were going but wanted to bring it back with a proper adventure for the boys.
But if you just turned dark at the end that would feel like a cheat.
You have to feel like you were warned and then forgot the warning.
Twists only work if you have a fair chance to work it out.
A dark turn in a show only works if you were sort of warned but preferred not to listen.
What made Mary decide to take a bullet for Sherlock?Well, she saved her friend.
There wasnt a lot of time to do anything about it.
Throughout the episode, shes really quite protective of them.
Shes actually better at all this than they are.
She regards them as a couple of talented amateurs.
She doesnt make a huge decision about it, she does what she can with no time to think.
So it was a big deal.
We dont ignore it.
We dont have John come back and say, Well Ive thought about it and its all fine.
If anything, the rift getsworse.
We decided if we were doing this were doing grief properly.
We were doing the consequences properly.
We dont skirt around it.
We dont just get on with the story of the week although thereisa story of the week.
Theres a big villain to fight.
But front and center are the consequence of Marys death and Sherlocks culpability.
He could have done better, its his lifestyle that killed her in the end.
Obviously, it wasnt his fault.
Mary tried to save his life.
We really went for it.
Obviously, Im not the person who makes the judgment.
If we do pull that off that will be great.
I think its safe to say we couldnt do Sherlock Holmes and Dr. Watson without Holmes and Watson.
But nobodys safe and consequences are everywhere and theres some emotionally grueling stuff coming.
Theres proper humor too.