Warning: The 'Riverdale' Musical Episode Is Going To Make You Scream In Its Final Moments

The CW's Archie Comics drama Riverdale has made a name for itself thanks to its breakneck pacing and multiple jaw-dropping twists. So what happens when you combine the show with Carrie, a classic horror film with an iconic and bloody climax, and throw in some big musical numbers? Well, it should come as absolutely no surprise to hear that the ending of Riverdale's musical episode is going to make you scream.

It's school musical time at Riverdale High, and Kevin (Casey Cott) is directing Carrie: The Musical, starring none other than demanded-the-lead-role-or-else Cheryl Blossom (Madelaine Petsch), Betty (Lili Reinhart) as the girl next door, Veronica (Camila Mendes) as the popular mean girl, Archie (KJ Apa) as the boy next door and other Riverdale High faves in supporting roles. Jughead (Cole Sprouse) isn't in the musical because duh, he doesn't sing and dance, but he's still included in all the drama since Kevin asked him to record a documentary about the making of Carrie: The Musical.

And if you're thinking, "Wait, there's a musical version of Carrie?!" You are not alone. "It very infamously flopped on Broadway so it closed after a week and I was devastated," executive producer Roberto Aguirre-Sacasa tells me on set while on set filming the musical episode. "I did not get to see it. The flop was legendary." But hardly anyone has seen it. He managed to get his hands on a bootleg and secret recording of the show, and it fed his obsession even more. So after working on the 2013 film remake of Carrie with Chloe Grace-Moretz and hearing about some of his friends working on the off-Broadway revival of the musical, Aguirre-Sacasa knew he had to find some way to bring it to life on Riverdale. "It's been a long road — my entire life has been leading to this moment, where I can combine my obsessions like Archie and Carrie and musicals and horror and bring it all together," he says.

Riverdale's musical episode uses the music and lyrics from the off-Broadway revival, which is what the series was able to get licensing for. "Some of the musical numbers are presented like they would be in the actual musical and the other musical numbers, we're doing them more in service of the actual Riverdale story," Aguirre-Sacasa says. "It's a mix where some of our numbers are straight out of Carrie and some are telling the story of our characters."

And beware: Aguirre-Sacasa was directly inspired by the movie in crafting the episode's ending. "Carrie the story has one of the most iconic, shocking endings, which is the destruction by Carrie of her high school at prom night," he says. "We felt that if we did an episode that was inspired by Carrie, we had to have a huge shocking ending that could be compared to the ending of Carrie."

While Aguirre-Sacasa isn't here to spill any spoilers, he did tease that the final moments of the hour will serve as payoff for a storyline he's been trying to do on the series for a while. "There is this one story we had been thinking about bringing back and so we thought up the most shocking way to end the episode with that storyline," he says.

This episode will definitely be a night to remember for how it will affect all the dynamics between the characters moving forward. Since Archie's dad Fred (Luke Perry) offers to build the sets for the musical, he ends up finally coming face to face with the full weight of his son's betrayal by allying himself with the Lodges.

"The relationship between him and his dad and the relationship between him and Hiram [Mark Consuelos] changes in this episode," Apa says. "We see that he's trying to rekindle that relationship with his dad because he's getting too deep in with Hiram. There are certain decisions he has to make in order to make it clear to Hiram that his priorities and his loyalty are with his dad."

For Betty and Veronica, right now these BFFs are more like frenemies now that Veronica's knowledge of her father's plans for Southside High to be turned into a prison have been exposed. Reinhart promises a "big emotional" moment is definitely coming in this hour for these two former friends.

"Betty and Veronica are having friendship problems and the musical will force them into an environment together, which is like a pressure cooker for both of them," she says. "It forces them to confront their issues." But that's not all the drama Betty's dealing with during the musical. "This episode is also very heavy with the Alice [Mädchen Amick] and Betty storyline, where Alice is feeling like her family is falling apart with Chic [Hart Denton] not living at home anymore and she doesn't want to lose Betty," Reinhart adds. "She's terrified of her whole family abandoning her so she's desperately clinging on to her daughter in any way she can."

Mendes is looking forward to getting Betty and Veronica's friendship back on good terms. "Through the musical, they try to make amends," she says. "They have such a close friendship and their fight unfortunately had to do with stuff that neither of them had control over. But there is a story of betrayal in it and dishonesty so that's what is keeping them apart. So in this episode, Betty learns how to forgive Veronica."

Although Betty and Veronica are always rivals in the comic book source material, Mendes loves how Riverdale has made the two girls real friends instead of enemies. "I always want Betty and Veronica to be a duo, the core of the show," she says. "They're a team and that's how it should always be. Their fight, at the center of it, shows how much they care about each other and how much they can be hurt by each other's actions."

For the star of the musical, Cheryl is going to have a lot on her mind in this episode. Not only is she constantly at war with her own abusive mother, but she's finally found love with Toni (Vanessa Morgan). "Her relationship is finally blossoming in this episode and you see a really beautiful moment with her and her significant other," Petsch says. "Her and Toni's relationship is going to grow and you see their connection and the support from her girlfriend in this episode."

Finally having support from someone in her life is "such a relief" for Cheryl, who has always been on her own. "She's constantly facing so much conflict from her family," Petsch says. "She's never had someone care about her like this before and makes her feel strong and she definitely ends the episode in a really good place, which is so rare for Cheryl."

As for the long-simmering conflict with Josie (Ashleigh Murray) after Cheryl sent her a bloody pig heart borne out of her obsession in the first half of this season, expect a resolution to finally come in this episode. "Moving forward this is going to affect Josie positively," Murray says. "There are some things that go down between her and Cheryl, they go head-to-head in a duet and the outcome of that is good for their friendship."

But about that shocking ending ... Reinhart reveals that "the end of this episode affects every single person in Riverdale." Mendes adds that, "I think everyone will be shocked at how quickly a happy musical episode can turn dark." Sprouse elaborates a bit more, explaining that the final moments "end on a cliffhanger where something absolutely shocking and appalling happens."

"I have a feeling that the writers like to breathe joy for the first 40 minutes of every episode only for the last two minutes to be devastating," he says with a big grin. "We pick up on that same kind of narrative scheme and the ending is shocking and horrifying."

Cott warns that everyone needs to watch until the very last second of the episode, "because you're not going to believe what happens. It's crazy. You really can't predict what's going to happen." And Apa agrees that no one will be able to guess what's about to happen. "It's horrific," he says. "I don't think our show has done anything quite as dark before. I had the tingles. It's rare for me to become emotional in the read through and I was fully shocked. I've still got the chills. It's crazy." Murray didn't want to spill any spoilers but she did have offer up this warning: "People's jaws are going to be under the table and that's all I can say."

Does the end of the episode have anything to do with a very specific, infamous bloody scene ripped straight from Carrie? "There is lots of blood," Petsch says. "But maybe not in a way you think. When you watch the episode, you'll understand." And Aguirre-Sacasa laughs as he thinks back to how he almost forgot to include that bloody Carrie scene in the musical. "There will be blood," he says. "A lot of blood. Buckets of blood." This is going to be the Riverdale event of the season that you definitely don't want to miss.