Warning: this post contains spoilers for The Undoing.
It turns out that HBO’s murder mystery The Undoing is much more murder than mystery. From the beginning, charming pediatric oncologist Jonathan Fraser (Hugh Grant) was the main suspect in the horrific killing of a young mother from his son Henry’s prestigious private school. Throughout the series, Jonathan’s wife Grace (Nicole Kidman), a clinical psychologist, learned that he’d been hiding just about everything from her: he was fired from his job, had affairs, borrowed money from her father and had a sister who died under his care.
All signs pointed to Jonathan being the perfect candidate for murder—so much so that he seemed too obvious a choice for a crime thriller. But in the last installment of the six-part series, the big twist was that there was no twist at all, when it was revealed that Jonathan did indeed smash a young woman’s face in with a hammer. He was the person he claimed he never could have been. TIME spoke to Susanne Bier, the director of The Undoing and the filmmaker behind Bird Box and The Night Manager, about the big reveal, the choice to cast Hugh Grant, the show’s popularity and more.
TIME: Jonathan was the obvious suspect from the first episode. How did you hope viewers would react to the reveal that he did, in fact, murder Elena?
Susanne Bier: In a way, the whole conceit was to do this hand-holding with Grace. What Jonathan was doing with the audience is pretty much what Jonathan is doing with Grace. He’d admitted that he’d been unfaithful. He’d admitted that he was not quite the man she thought he was. Then he very consciously and diligently rebuilt her trust in him until she couldn’t trust him any longer. Grace suffered from what she told one of her clients in the beginning of the series: Are you seeing what is really there? Or are you seeing what you want to see? It’s very deep in human nature that we see what we want to see. You can see the series philosophically is about that. It’s about our own inability to deal with reality and our constant desire to twist our perception into a reality we find more promising, convenient and likable. That’s what the series was about. There was never any question that it could be anyone else.
Part of the reason it’s hard to believe that Jonathan could really have done it is that Hugh Grant is such a charming actor. Could you have pictured anyone else in this role?
Part of the reason why Hugh Grant wanted to do it and part of the reason we wanted him to do it is because he’s such a charming actor with a lot of depth underneath. We love Hugh Grant and we want to love him, as does Grace. The first thing I said when I started on my very first meeting with [creator] David E. Kelley and Nicole Kidman was that I think we should get Hugh Grant to play it because of the charm and also the kind of sadness he has, which is also incredibly endearing and likable.
It’s unusual for a crime thriller to have the murderer be the person viewers suspected it might be all the way through. What were the challenges of pulling that conclusion off in a compelling way?
It was very challenging. Part of what we set out to do was to seduce audiences that maybe it wasn’t him and then to have the suspicion go in all sorts of directions, and then have it come back like a boomerang. Episode six was massaged in many ways before the final version.
The Undoing is based loosely off of a novel by Jean Hanff Korelitz. How faithful did you want to be to the source material? How much freedom did you feel you had to play with it?
David E. Kelley, in our first conversation, told me that he was going to use the book for the first two episodes. The book is called You Should Have Known. The fundamental theme of the book is that it doesn’t really matter how brilliant or insightful you are, you can still be fooled. You can still let yourself be fooled into thinking that things are different. And that whole thing of “you should have known” is the core of the series as well as the core of the book.
In an earlier episode, we learn that Grace walked by Elena’s studio the night of the murder and doesn’t remember it. What are we supposed to make of that given what we know now?
What she does is tell the truth. We do see her walk a lot. She walks all of the time. She just happened to walk past.
Henry is around the same age that Jonathan was when his sister was killed. Was that an intentional statement about the legacy of childhood trauma?
It was certainly suggested in terms of childhood trauma, but also, I think for Grace there was this concern: is it really possible that my son is a sociopath? Or is Jonathan using that potential because Grace now knows? And the latter is the right explanation.
The show was the best first season launch ever for HBO in your native Denmark, and very popular in Europe in general. What do you think accounts for its popularity there?
Very fortunately, it’s been incredibly popular everywhere. Nicole Kidman and Hugh Grant are an interesting and sexy couple. I think we were very lucky this time and made a show which people are really excited about.
A lot of people compared this show, at least before watching it, to Big Little Lies, given the combination of David E. Kelley, Nicole Kidman and HBO. Did you ever feel like you were expected to fill a Big Little Lies-shaped void for viewers?
I didn’t. Of course I knew there would be conversation, but I feel it is a very different show. I felt that Big Little Lies is a show more about female friendship than anything else. I feel this show is very much about a couple, about who you can trust, in a different way, and a lot about men and women.
This is a miniseries, but we have seen several successful miniseries that were intended to end come back for a second season. Is there any more material here you’d want to explore in another installment of this series?
I’d love for David E. Kelley to write a season two, but at this point in time it’s only wishful thinking. There are no plans. I’ve got no idea whether David would be remotely interested. There hasn’t been a conversation about it.
There has been a lot of chatter on the Internet about the coats Nicole Kidman wears, and even the helicopters that were used in the finale. What appealed to you about the underbelly of this very ritzy New York City world?
I feel like it’s been a character in the show on its own. New York City is on one hand so monumental, and there’s something sort of very clear and kind of architecturally strict about it. Like, the grid. And then, it’s so, in another way, out of control. I like that complexity and I liked that mixed thing. I felt that Grace’s walking at night and walking in the city emphasizes that.
There’s one last thing that’s been looming over the series. Do you think Henry can finally get his dog now?
It’s really funny—at some point, in the ending, we had Grace going in and buying a dog. Then it kind of became too many endings on top of endings on top of endings. But yes, I think Henry will get his dog.