SPOILER ALERT: Do not read if you have not watched “Chapter Ninety-Six: Welcome to Rivervale,” the sixth season premiere of “Riverdale.”

The sixth season of the CW’s “Riverdale” certainly opened with a heart-stopper.

With narration by Jughead Jones (Cole Sprouse), the show introduced viewers to a parallel town to the titular one: Rivervale, where things were so dark its residents took part in ritual sacrifice, leading to the demise of Archie Andrews (KJ Apa) when the entire town came together to offer him up. Cheryl (Madelaine Petsch) was the one to commit the act, reaching into his chest and yanking out his heart, leaving it to pulse in her palm for a few seconds to an enraptured crowd.

But how did they get here? The “Twilight Zone”-style narration implies this could be an alternate universe. Archie waking up at the start of the episode telling his girlfriend Betty (Lili Reinhart) that he had a dream about a town called “Riverdale” might be foreshadowing that the machinations here are some kind of “from the mind of” scenario. Some might even think this is a story Jughead is working on. No matter what transported these characters to this different place, though, the experiences they have while within this five-episode mini arc are designed to continue the plot from the end of Season 5, creator and showrunner Roberto Aguirre-Sacasa tells Variety.

“I’s very much in-continuity, so we’re not picking up in [Episode] 606 as we would before it. It is very much continuing, in a strange way, all of the episodes from the end of Season 5. The idea was, ‘Let’s swing for the fences, let’s do something that fans have been asking for,'” Aguirre-Sacasa explains.

What fans were asking, he clarifies, is, “‘When is “Riverdale” going to go full-horror, full-supernatural?’ That’s always a big decision and a big swing, but it felt like, ‘Oh well, this could be the time to do it.'”

In doing so, the beloved characters “would be allowed to do things that they might not be allowed to do in Riverdale” — hence Archie’s loved ones like Betty and Jughead agreeing to sacrifice him. But because storylines had to carry over from Season 5 and through the rest of Season 6, this was not a chance to completely reboot who people were or what they wanted — or even put them in brand-new romantic pairings. Jughead and Tabitha (Erinn Westbrook) moved in together in Rivervale, following the natural progression of the relationship they had at the end of Season 5, for example. Veronica (Camila Mendes) and Reggie (Charles Melton) wanted to open a casino, and Rivervale allows them to explore that opportunity.

“I think if we had proposed everyone in Riverdale getting together to sacrifice Archie for their personal gains, eyebrows might have been raised. As it was, even in Rivervale eyebrows were raised, but we allowed ourselves to push characters a little bit further and go a little bit more extreme. Like for instance, in [Episode] 602 you’ll see a different sides of Veronica and Reggie, you’ll see a different side to Tabitha and Jughead. Everyone gets to be the darkest version of themselves in Rivervale, which is fun,” Aguirre-Sacasa says.

There are “huge levels of danger” in Rivervale, Aguirre-Sacasa continues, noting that Archie is only the first casualty. The five-episode Rivervale arc will continue some of the dangerous threads of Season 5, including the Trash Bag Killer and Abigail’s (also Petsch) curse, Aguirre-Sacasa says. Witch Sabrina Spellman (Kiernan Shipka) reprises her “Chilling Adventures of Sabrina” role during this arc, as well.

“The tone is more ‘Riverdale’ than ‘Chilling Adventures of Sabrina,’ but it’s definitely more out there than we have been on ‘Riverdale,’ as hard as that is to imagine,” Aguirre-Sacasa says of the episodes.

For the audience that wants to figure out exactly what is going on and why, Aguirre-Sacasa says they have embedded clues in both “dialogue and the background of the visual world.” One season premiere element that may have seemed to have a double meaning was when Jughead got sentimental with Archie during the pancake-eating contest. But Aguirre-Sacasa says that was because Jughead knew “he’s going to sacrifice Archie and asking for forgiveness before the sacrifice,” not that what was said was something an unconscious Archie in the Riverdale world was bleeding into Rivervale.

“Archie is not in a coma because of the bomb,” Aguirre-Sacasa confirms of the Riverdale world, referencing Hiram’s (Mark Consuelos) act of aggression against the hero at the end of Season 5.

In Rivervale, though, Archie is really dead, he continues.

At least for now. Since this arc will progress stories into the later episodes of the season, when things are back in the usual setting of Riverdale, it’s hard to imagine he’ll stay dead for long. Aguirre-Sacasa says these episodes have opened the door for the writers to lean even further into the horror genre and “let the supernatural creep in a little bit more,” and right now the character of Archie seems the most rife with possibility in that area.

“Riverdale” airs Tuesdays at 9 p.m. on the CW.