‘Pretty Little Liars: Original Sin’ Creators Break Down the Twin Theory and That Haunting Halloween Murder

Roberto Aguirre-Sacasa and Lindsay Calhoon Bring chat with TheWrap about Episodes 4 and 5 of the HBO Max series

Warning: This post contains spoilers for Episodes 4 and 5 of “Pretty Little Liars: Original Sin.”

“Pretty Little Liars: Original Sin” wouldn’t be a horror show without without scaring up a Halloween storyline, and the series did just that with a classic costume party that ended in bloodshed at the end of Episode 5.

The latest two episodes, which dropped on HBO Max last Thursday, kicked the series into high gear as audiences got a taste of how the girls are going to have to confront their own traumas while also unraveling the mystery of A — who appears to be getting more murderous by the day.

The show left off on a haunting note with another murder in Millwood, and the girls (and audience) were once again left with quite a few more questions than answers. Lucky for us, creators Roberto Aguirre-Sacasa and Lindsay Calhoon Bring sat down with TheWrap to discuss both episodes to offer some clarity ahead of Season 1’s second act.

TheWrap: We obviously have to chat about this twin theory. I cannot decide if I think it’s really Karen, or if it’s Kelly. My mind changes multiple times per episode.

Lindsay Calhoon Bring: You’re on Faran’s journey.

Robert Aguirre-Sacasa: I mean, obviously, there’s such a huge tradition of creepy twins in horror movies — in the original IP, in ‘The Shining,’ in the original ‘Carrie.’ That’s always such a fun staple, and it was a little bit late breaking that we were going to have twins. I think it was sort of like, ‘Oh, we love what happens to Karen, but we love the character of Karen.’ The only bummer about that is we were killing off a great character, and that character is always helpful to have on a show. So we were like, ‘What if she’s a twin?’ You can’t do a twin story without at least someone wondering which twin died. We didn’t want to make it all about that, and we wanted to keep it emotionally and psychologically as grounded as humanly possible when you’re doing a show called ‘Pretty Little Liars: Original Sin.’ I will say, we’re really proud of it. I think it turned out great but there was a little bit of trial and error [because] we didn’t want to like, oversell and over lean on this trope.

Bring: Much like our audience, we kept our actress Mallory Bechtel guessing, and she’s incredible. Very early on, we knew that ‘Wow, she can do this.’ She’s such a strong, amazing actor and she has so much nuance between playing both Karen and Kelly. … We had so much fun watching her and writing the story for her was really wonderful.

I was chatting with her recently and she told me that she didn’t know anything more than what was on the page. That’s really impressive.

Aguirre-Sacasa: To Mallory’s credit, sometimes when actors are forced to do things like that, all you get is a million questions and you don’t really want to answer them. I don’t think she ever asked me like, ‘Who am I really? What am I doing in this scene?’ She just went for it.

Bring: I think she was as curious as as everyone else was, but she was so game to play the part. I said ‘Look, does the character say Kelly or Karen?’ I think she took that to heart, which is great because when the girls are supposed to think [she’s] Kelly, [she’d] better be Kelly. So she she played it really well and she was really fun and along for the ride and just had an amazing attitude about it.

There’s that one scene in Episode 5 at the Halloween party that I couldn’t stop thinking about after I watched. There’s so much nuance it’s impossible to tell if it’s Karen or Kelly.

Bring: Watching Zaria and Mallory do scenes together, it was really delicious. They really played those parts so well and have such a great story together over the season that we really love. It’s very unexpected.

In Episode 5, it feels like we really hit the gas. I liked opening on that scene where you see the girls’ moms actually really bullying Angela Waters. Can you tell me more about that scene?

Aguirre-Sacasa: Halloween is such an iconic holiday. And obviously the “Halloween” movie begins with such a great flashback on “Halloween,” [and] we wanted to do the same. All of the girls’ mothers, we’ll see their relationship with Angela — the same way we did with teen Marjorie and Angela smoking. We see that for each of the girls. We wanted to do one episode where you saw all of the teen moms together and it felt like Halloween night is the perfect night to do that. You see the casual cruelty of the girls that night, and the humiliation that Angela [feels]. I will say, there’s a lot more to unpack in the dynamic between the teen moms and Angela. Halloween is a night of pranks and it’s a night of hell raising and things like that. I think [that scene] was to really build up Halloween night as an iconic night in horror movies. The ‘PLL’ Halloween episodes are legendary. The idea was to really elevate that episode and make it special.

Bring: Everything, too about that opener was so specific for us. It’s even the fact that Angela is the only one not in costume. The girls invite her out but she’s still othered because they chose to be a group of five. They’re zombie Spice Girls, and then there’s Angela. Everything about that was so designed to make Angela feel separate which is the worst thing you can do to a person is bully someone and make them feel like they don’t belong. And as Roberto said, to have that on Halloween night, this felt like a very strong horror moment — an internal horror moment for Angela and an external horror with what happens to Tyler.

I’m glad you brought up Tyler. That murder scene was wild! I don’t think I was expecting for A’s next victim to be Tyler. Am I just totally not paying attention?

Aguirre-Sacasa: No. So I mean, I will say he’s so horrible. He’s a great villain as well. And he’s so horrible to Tabby. He’s horrible to all of the girls at the Halloween party and he’s doing it right under A’s judgmental eye. There’s such a weird, almost puritanical morality to these slasher horror movies and it feels like when when teenagers get killed, they’re usually being punished for something, be it having sex or being being cruel or like lying or, you know, all the things that teenagers do. One thing that Lindsay talks about a lot too is what’s great about that kill is it’s not a young woman getting killed brutally in a bathroom, right? It’s usually a half naked young woman in the slasher movies who has been brutalized and killed. So I think there’s something that feels right about it in that moment.

Bring: I agree. Brian Altemus was such a fun actor playing that role, and we always talked about Tyler being the embodiment of toxic masculinity. [In] that showdown with Tabby, everything Tabby’s saying is right and I think it harkens back to Episode 2 with the release of the video. Of course, the girls did release that video and that was a horrible thing to do. We always talked about ‘Gosh, the girls are getting in trouble. They’re getting their comeuppance. But what about the guy who’s videotaping the young drunk girl who knows where that’s gonna go? What’s his comeuppance?’ Tabby calls him out for it when they have their big showdown at the party, and she’s right. I think A hears all of it, A sees all and to Roberto’s point, takes a stance against bullies and Tyler’s a bully too. I think he had it coming.

Oh yeah, I don’t feel bad for him. It’s definitely one of those murders where you know he had it coming.

Aguirre-Sacasa: Well listen your surprise is good. It’s a good horror jolt. Like you can’t do Halloween night without someone getting killed at the house party.

The last thing I wanted to touch on is Imogen and Tabby opening up about their traumas to each other at the end of the episode. Are they going to dive into what happened, and is it going to play a big part in the story going forward?

Bring: Yeah, we knew when we were developing the characters that each girl would have a core wound, and we did talk about this being a grounded horror show too and tackling real horrors that girls face every day. And unfortunately, those horrors do include assault and statistically, you can find friendship in that and bond over that trauma. We knew that we wanted to follow each girl individually until they felt safe enough and trusted each other enough and earned that friendship enough to open up to each other, and for us, that was by the end of [Episode] 5. Tabby and Imogen have been living together. They’re one of the great love stories of the show. They really do become sisters, and in Episode 6, they do unpack their stories. They are survivors. They do support each other. Hopefully this isn’t a spoiler, but in that sisterhood and friendship and the show that we’ve set up, they do lean on the people they love and trust the most which is their friends, and they do come together to help each other.

Aguirre-Sacasa: That’s a mystery that we follow concurrent with the mystery of A, and in a weird ways is as big a mystery and is as emotionally weighted. There’s definitely huge resonances between the A mystery and what happened with Imogen and Tabby. It is about cycles of violence against young women. So these two very big, potent threads kind of come together until the last episode.