SPOILER ALERT: Do not read if you have not yet watched “Chapter Twenty-Six: The Tell-Tale Heart,” the 13th episode of the second season of “Riverdale.”

Archie (KJ Apa) learned some dark truths in the latest episode of “Riverdale” — but the secret of Betty (Lili Reinhart) and Alice’s (Madchen Amick) murderous cover-up looks to be safe. For now.

“When I started ‘Riverdale,’ I didn’t know it was going to turn into a show about dead bodies and cover-ups and criminal investigations and mobsters and all that. I really thought it was going to be ‘Archie’s trying to get the band together!'” creator Roberto Aguirre-Sacasa says.

Although the show has told typical high school drama tales, including pep rallies and dances — and will again with an upcoming episode designed around a theater musical production — the central mysteries of the show revolve on much more adult fare, including a murder mystery of a teenage boy in the first season, a serial killer stalking town sinners in the first half of the second season, and now a dive into a “Godfather”-style powerful family in the second half.

“The truth of it is ‘Riverdale’ has never been a realistic portrayal — it’s always been heightened, and it’s always had a crime element. I would say it’s sort of a genre show. This is the norm, as opposed to high school elections,” Aguirre-Sacasa says.

In “Chapter Twenty-Six,” Archie learned that the FBI agent pressing him for dirt on Hiram Lodge (Mark Consuelos) was not a real government official but instead a trusted informant of Hermione Lodge (Marisol Nichols), sent to test Archie.

“He was going to be a FBI agent originally, and [executive producer] Greg Berlanti said, ‘Careful with the FBI stuff and Archie going undercover for the FBI and wearing a wire.’ He was like, ‘Archie shouldn’t wear a wire. We did it on “Dawson’s.” People didn’t like it,'” Aguirre-Sacasa admits.

This made the writers switch to the idea that “Agent Adams” was an alias and that he was actually Hiram’s informant. But as they were writing the episode, Aguirre-Sacasa says, “We thought people might think he was Hiram’s, so we made him Hermione’s.”

After not only refusing to bug Hiram’s office but also confiding in Hiram about the agent who was threatening his father’s business, Archie passed that test, and Hermione revealed herself to him and welcomed him to the family.

“Archie started on a darker path, I think, in the first half of the season,” Aguirre-Sacasa says. “When Fred was shot and when the Black Hood had his gun on Archie, I think Archie felt powerless and paralyzed, and part of his journey this season is, he never wants to feel that way again. And there’s something attractive about the way the Lodges do business, and there’s something attractive about the way Hiram yields power, that Archie’s drawn to. That’s kind of what we’re exploring in the second half of the season as Archie gets deeper and deeper into the Lodge family businesses.”

This will put Archie at odds with his father Fred (Luke Perry), and as episodes go on and dealings get more complicated, Hiram and Hermione might also see more conflict between them.

“They’re like the Macbeths — a scheming couple,” Aguirre-Sacasa says. “We’ve been playing them in lockstep, so I think coming up we might get back to them disagreeing about certain things.”

When Hiram was first introduced, Aguirre-Sacasa says, he “sort of put Hermione in her place.” Yet, as “Chapter Twenty-Six” showed, she holds more power in the business than even he might realize.

“As the season’s been developing we wanted to make sure Marisol the actor had great stuff to play and Hiram and Hermione were more equals — that she wasn’t just the gangster’s mole or Michael Corleone’s Diane Keaton, home with the kids. We’ve been trying to build her up to be a more formidable player in this,” Aguirre-Sacasa says.

Archie may get dragged deeper into dirty deeds done by the Lodge family as episodes continue, but Betty and Alice have already been dragged into a pretty bad one by covering up the murder of a drug dealer that occurred in the Cooper family kitchen.

Aguirre-Sacasa admits that “repercussions” of that murder will be felt for “most of the rest of the season.” Not only will the show explore what actually happened in the kitchen but also the chain reaction that the cover-up sets off.

“One of my favorite movies was a suspense movie called ‘The Deep End’ with Tilda Swinton where her son gets caught up in a murder and Tilda Swinton is a suburban mom who has to cover up the murder,” Aguirre-Sacasa says. “It’s a very Hitchcockian story. That kind of was the inspiration for this episode, which was seeing Alice and Betty cover up this thing they shouldn’t cover up. Of course it’s shaking loose a lot of things, like the truth about Chic. We’re going to find out much more about her relationship with FP [too].”

After Betty confided in Jughead (Cole Sprouse) about the cover-up and they got rid of the dead drug dealer’s phone and car, he told his father FP (Skeet Ulrich), who decided he didn’t want them to make the same mistake he made with Jason Blossom. He buried the body and told the group that it wouldn’t go any farther.

But the darkness that lives within the characters — especially Chic (Hart Denton) — ensures that even if the body stays buried, the drama from the event will not.

“One of the reasons Betty reached out to Chic was to kind of understand her darkness and to see if she recognized something in Chic that she saw in herself,” Aguirre-Sacasa says, promising the audience will learn “so much more” about Chic in the coming episodes. “We’re very much continuing that story. But I think it takes some big twists and turns before resolution.”

And don’t count out the Black Hood from the first half of the season, either. Betty did remove the literal hood from the fire, after all, so Aguirre-Sacasa says it is “safe to say [that story] is going to continue — but maybe not in the way you might expect.”

“Riverdale” airs Wednesdays at 8 p.m. on the CW.