The very dark comedy Thoroughbreds is an engaging, slow-burn of a ride that will leave you thinking about things. Not necessarily murder, but how you get to that point.

The story follows Amanda (Olivia Cooke) and Lily (Anya Taylor-Joy), two teenagers from well-off families who were once best friends in middle school but who grew apart. When they reconnect, with Lily tutoring Amanda for the SAT’s, an unlikely bond is formed. Amanda professes to have no feelings whatsoever, while Lily feels too much. But it’s through this strange friendship, the two decide to kill Lily’s emotional abusive stepfather (Paul Sparks), with the help of the local drug dealer (Anton Yelchin). Let’s just say things do not necessarily go as planned.

ScreenPicks had a great conversation with writer/director Cory Finley about his feature film debut – and here are seven things we learned.

Q: Where did you come up with this story?

Cory Finley: It was sort of a long, strange process. It started with a play, and it was in its early drafts. It was really different and was about adult characters, kind of in the same world, but it was always me diving into my own mixed and uncomfortable feelings about wealth and privilege. There was always loads of stuff going on, and always some kind of moral question at the center of it. But it took a lot of different shapes and it kind of finally solidified into this, kind of psychological thriller shape. When that started to happen, it started to be clear to me that it would work better as a film than as a play, and I was lucky to find producers and cast and all of the above to make that happen.

Q: What kind of things were going through your head and did you have people in mind that you wanted to cast?

CF: I did to some degree. I didn’t write with actors in mind originally, but as soon as we started talking about doing it as a movie, it became clear that that was the key question: Who would play these two roles? I said it was a psychological thriller, but it, for me, it’s always, at its core, the story of this friendship and this really kind of two-hander that’s totally carried on the back of its two lead actors. I was just a huge fan of Olivia [Cooke]’s from a bunch of her movies. I just recently seen Me, Earl, and the Dying Girl… I was struck about a lot of things about her performance, but particularly just how great her comic timing was, and how sharp she could be with a deadpan, and for the character [Amanda] that is almost totally dependent on that range.

She was an easy first choice for that role. And then, around that time, The Witch came out in theaters, and I’d heard about the splash it had made at the previews here at Sundance, and really loved that movie and loved Anya [Taylor-Joy] in it.

We had some great conversations early on and kind of fleshed out their backgrounds as characters. It was amazing to see them kind of like get into lockstep and Anya would tell you, or either one of them would tell you about the way they both started to all just kind of like mirror one another’s movements, reflexively. They just got so deeply on the same page.

Q: Do you feel like that it’s a real possibility to live without any feelings?

CF: [Olivia] takes a very extreme character and makes her very, very human. I think we talked about how, you know, she says she feels nothing, and I don’t know if you can totally take her at her word. She certainly has an emotional logic that is different from most people’s, but I think, I hope that by the end of the movie you feel that she’s… even if she’s not feeling things in the way that the rest of us do, that she’s driven by some kind of a human connection and she does certainly care about things. I was sort of interested in like what components of a personality are necessary to be a good person. And can you be a good person without certain things that we assume all normal and good people need to have. That was the core question of that character for me.

Q: What was a theme that struck you the most when you were writing it and when you were making it?

CF: [Amanda is] asking whether the world’s ultimate moral good is by getting rid of someone who causes more pain unbalanced than he does good, you know? That’s sort of like a philosophical conversation. Someone who’s not at all bound by any traditional moral instincts, but still has a very rigorous, inquisitive mind, like us. The kind of conversation I imagine they’d have and yeah, so that was all sort of the core of the story for me.

Q: Seeing the late Anton Yelchin hurt my heart all over again. How was it working with him?

CF: Me too. Yeah, I think it was. But he accomplished so much and he worked with such an incredible array of filmmakers so I feel super lucky to have gotten that chance [to work with him]. I think all of us did, that was all on the film, and he was such a just … in this movie, in his own, in any of his performances and his artwork, he’s an amazing photographer as well as an actor. He’s just such a unique anchor and sort of student of film and art, and just the absolute loveliest human being on top of all that, so certainly he’s very missed and we’re all very lucky to work with him.

It was like talking to a professor of film theory talking, but, you know, also the most sort of playful and puckish version of one. He had such a truly intimidating knowledge of film. I felt like I knew something about movies before I got to set, but as soon as we started talking genre comparisons, I was just like, “This guy is doing laps around me and has incredible insights about all of the movies he’s talking about, too”. But in a way that was never threatening. It was very, just so friendly and open, and just the best guy.

What have been some of the best reactions that you have gotten about Thoroughbreds?

CF: It’s been really fun to see the variety of them. I think it’s always cool when people kind of connect with it as a comedy and I always love when I hear big laughs in the audience. And when people give themselves permission to laugh at it. It is, you know, it’s quite dark, anxious, stuff, but I think when people let themselves enjoy the comedy of it, I love that.

My favorite reactions are always when it gets people on an emotional level, and when they’re able to invest in the relationship. It’s certainly kind of a cold, extreme movie in a lot of ways, but when people connect to something about the characters and when they feel something about their … the way they connect to one another, that’s when I feel most gratified.

What did you find was the most gratifying thing through this whole process? The writing, or the directing, or sort of a combination of both?

CF: Good question. The writing is always has been sort of like, elemental power for me. That’s like the core of the enterprise, in a way. But that being said, just the joy of directing is so much – I kind of hate writing. It’s sort of the worst, and it’s so lonely. But I love directing, and I absolutely love the editing process. That was a whole kind of revelation to be in there. It had so much about what I love about writing, but my editor on this movie was just one of my favorite people, Louise Ford. She’s an amazing film editor, and that process is such a joy. So it’s hard to pick. I think they work in complementary ways, but I really, really love directing.

Thoroughbreds opens in limited theaters this Friday. Definitely check it out.