Warning: This article contains spoilers about the finale ofThe Girl Before.
Even the cast ofThe Girl Beforedidn’t seethatending coming.
In the present day, Jane finds herself in a similar situation when she realizes what Simon has done.

Ben Hardy and Jessica Plummer in ‘The Girl Before.'.Amanda Searle/ HBO Max
Jane decides to be open with the police about what really happened, both for her and for Emma.
What did you find most instructive for bringing your character and their trauma to life?
A therapist was one of them, who is a specialist in that specific trauma that Emma went through.

Gugu Mbatha-Raw and David Oyelowo in ‘The Girl Before.'.Amanda Searle/ HBO Max
Like, why wouldn’t she leave?
Why didn’t she tell the police?
And just being able to get those answers.
Ben, how did you tap into the mind of a killer?
I personally don’t think he’s psychopathic, but I don’t know.
So much of my preparation was [seeking to understand him]…
I can’t play someone if I think them to be entirely evil.
I know how insane that sounds, but that kind of brings me to my point.
I was worried I was going to drive myself insane doing these mad journalings of Simon’s logic.
What could lead them down that road?
So, I was trying to sympathize with that.
Were you guys surprised by Simon being the killer?
If so, who did you think the killer was instead?
And then I’d be like, oh my God no, he’s definitely sort of bad.
You start ending up sort of understanding them as human characters.
So I loved being kept guessing and I totally didn’t see it coming with the character.
But then, like I remember seeingThe Undoing, and thinkingthere’s no way it’s Hugh Grant.
They managed to make that be the reason that you were wrong-footed there.
So weirdly, seeing that show actually threw me off really.
So that, I think, is a testament to the writing.
And I did not see that coming at all.
Who did [I think did] it?
I’m not quite sure, maybe the house could have done it.
It could have just been an accident.
HARDY:That would’ve been such a dud of an ending, though.
Do we think Simon’s done something like this before, or he just snapped?
HARDY:I will tell you his backstory right now, real briefly.
I don’t think he’d ever done this before.
I’m never going to be cuckolded," essentially.
And when he’s there in that final moment, he’s there to win her back.
But it becomes abundantly clear that’s never going to happen, and then he snaps.
Do you think there’s a future for them?
And that, to me, was really interesting.
So it’s like, did he learn the lesson?
Is he looking for another Jane or Emma, as it were?
But I am banking on the sequel, which will be The Girl After The Girl Before.
And Gugu and I are going to go at it all over again.
[Both laugh]
Jessica, do you feel like justice was done for Emma in the finale?
So when we were shooting, I know that quite a few different versions of an ending were shot.
Also, I remember getting different versions of the script and there was constantly changes happening.
And whilst we were shooting it, I didn’t ever read Jane’s storyline.
So the ending for me, when I was filming, was when Emma died.
I mean, all of it, I was weeping near the end.
I definitely feel like Jane got justice for Emma, for sure.
This interview has been edited and condensed for length and clarity.