Riverdale type TV Show network The CW

Riverdale is a town that knows what it wants. Which is to say that it loves a good murder mystery, a good milkshake, and a good musical moment. And this week’s episode, more than any other, is going to deliver a musical moment (or 10) to remember.

With Riverdale High putting on a production of Carrie: The Musical — directed by Kevin, obviously —the Riverdale cast got to partake in the series’ first-ever musical episode. In anticipation of the hour, EW hopped on the phone with showrunner Roberto Aguirre-Sacasa to talk about what viewers should expect both on and off stage.

ENTERTAINMENT WEEKLY: You’ve said that the idea for a musical episode was floating around for a bit, right?

ROBERTO AGUIRRE-SACASA: This is something that we wanted to do since the birth of the series. The original idea for the show was that it was going to have more music and be more music-driven, and that one of the rites of passage that we would do is the kids all do the high school musical, which feels like something that a lot of kids in high school do, even if they’re not theater geeks. It was something that we wanted to do in season 1, but we didn’t have the real estate to do it, so we said, “Okay we’re really doing a musical episode in season 2.” Then it kept moving later and later into the season. We came to a point where it was now or never. We went for it, but because it was late in the season, it wasn’t like we could tell a standalone bottle episode. We still had to carry a lot of the season stories into that episode because it felt weird to put them all on pause, so we incorporated them.

And how did you decide on Carrie: The Musical?

I’ve been obsessed with Carrie since I even knew such a thing existed. And then I was obsessed with the musical when it was a cult Broadway flop, and I’m friends with the guy who revived it Off Broadway. I was so jealous that he was getting to revive it. I wrote the remake of Carrie, which was not a good experience, and I always wanted to reclaim Carrie as something that I loved and was one of my favorite things, and I feel now, through this episode, that has happened.

Was it difficult to incorporate the score into the story?

One of the reasons why the songs so seamlessly fit together is because in their DNA, Carrie and Riverdale have a lot of similarities: They’re finding high school characters under extreme circumstances. So at their core, they’re teenagers singing about the same things. As soon as we landed on Carrie, you start seeing immediate similarities because the Archie characters, and to a certain extent Stephen King’s characters in Carrie, they are teenage archetypes, so some things fell immediately into place, and then we let the story help select the songs.

Image zoom Katie Yu/The CW

Did you make any changes to the Carrie music to make it work for you?

We took “You Shine,” which is traditionally a duet between the good girl and her boyfriend, and in the show we repurposed it to be a song about friendship between Betty and Veronica, and we used that song to heal their estrangement and the tension between them. We took another song that’s the gym teacher singing and comforting Carrie, and we gave that to Josie and Cheryl and also made it about their friendship and their coming together. We found that the songs were universal, and they could help us tell the story.

I’m so looking forward to this musical really giving Cheryl her moment.

In season 1, because the mystery was about Jason Blossom, Cheryl was at the heart of it. In the first half of this season, Cheryl had great stories but she wasn’t quite at the forefront, so I’m excited that in the second half of this season, Cheryl’s had a really strong storyline that I think people are really responding to, which is exciting because Madelaine [Petsch] is such a star. When we landed on Carrie it was like, “Well, who’s going to be Carrie?” And it’s like, “Well, Cheryl.” Even though it kind of doesn’t make sense, in another way it does. She’s got great moments in the musical. There’s some shocking things in [the episode], that’s for sure.

What can you tell me about this Archie-Betty duet?

It’s funny, there’s definitely a contingent of fans out there who love seeing Betty and Archie together. Looking back at the pilot, the story was between Betty and Archie in a weird way. Betty wanted Archie to ask her to the dance, and Betty wanted Archie to be her boyfriend. It’s so funny to look at it now to see how far the show has evolved and the relationships have evolved. But it is nice to get a glimmer of Archie and Betty acting like onstage boyfriend and girlfriend. There are a couple of jokes about that. Jughead says a couple of nice, funny things about it.

Riverdale airs Wednesdays at 8 p.m. ET on the CW.