After a season of weird, soapy, maple-syrupy drama, Riverdale's freshman outing is quickly barreling toward its conclusion on The CW, and that means the hunt for Jason Blossom's murderer is finally -- truly -- on.

In Thursday's "To Riverdale and Back Again," Archie (KJ Apa) and Veronica (Camila Mendes) team up with Betty's (Lili Reinhart) mother Alice (Madchen Amick) to investigate the connection between Veronica's imprisoned father and Jughead's (Cole Sprouse) father F.P. Jones (Skeet Ulrich), who appears to finally be cleaning up his act. The dude even shaved!

What Archie and Veronica find, however, is nothing more than a newly cleaned trailer and a story that appears to back up what F.P. is selling, which is why it's such a shock when the episode ends with F.P. in handcuffs after the gun used to murder Jason is found in his home.

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So who's framing F.P.? How will Jughead react to his father's arrest? And will anyone believe Archie and Veronica when they try to tell them the truth? TVGuide.com recently attended a small press screening with showrunner Roberto Aguirre-Sacasa and stars Cole Sprouse, Skeet Ulrich and Luke Perry to find out what's next. Here's what we know:

It's all mystery from here on out: While the series previously tried to balance the show's natural soapy elements and the mystery of Jason's murder, moving forward the show will be fully embroiled in finding his killer. "Episode 12 is all about the mystery and the kids are trying to prove that F.P. was framed, but no one believes them," says Roberto Aguirre-Sacasa. "It seems like the entire town is going in lockdown to kind of railroad F.P., so it's kind of a little bit of a race against time. And then there's still kind of a couple of characters out there who think someone else may have done this to Jason Blossom, so it's a big mystery episode. [It] kind of drives the whole episode."

Jughead predictably won't react well to his father's arrest -- and it's only going to get worse: We glimpsed a bit of Jughead's reaction at the very end of Thursday's episode, but his pain goes much deeper than it appears on the surface. He's also being forced to confront more than just the possibility that his father is a murderer.

"Jughead as a character has a real fondness for a Riverdale that was once more pure and beautiful, a sort of like Peter Pan-like childhood of Riverdale that existed, at least my understanding of the character," says portrayer Cole Sprouse. "I think obviously as time goes on and these characters get darker and darker and the secrets get more and more revealed, he's one of those characters that's going to really struggle like the rest of the town and dealing with the fact that this town can be a place of legitimate darkness."

"But he's experiencing it very first hand, which of course is going to be even more complicated," he continues. "I think narratively, Jughead's most touching narrative is Episode 12. Episode 11 is a very heavy Jughead episode, but Episode 12 is even more so."

Cole Sprouse, <em>Riverdale</em>Cole Sprouse, Riverdale

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It's time to get out the tissues, because the jailhouse scenes are emotional: Sprouse counts Episode 12 as his favorite, noting that the jailhouse scenes between father and son are his favorite of the season. And according to Ulrich, things get pretty emotional. "There's a lot of disappointment, a lot of secrets still being hidden. It's quite intense."

F.P.'s arrest will also force Fred to reconsider their relationship: "You know the old saying 'You don't know who your friends are until the shit gets deep?' I think when it gets deep with him it really makes me stop and think about what this friendship is, the history behind it, and is it somebody I can be friends with going down the road," says Luke Perry. "I have to set an example for [Archie], so that's the interesting flip of the coin there for me, to see how that goes down. Because I value friendship so much. And what's great about it is, I guess the only thing that I could value more than friends would be family and this brings it all back to the place where I gotta choose."

Despite knowing something about Jason's murder, F.P. doesn't know who's trying to frame him: We all know that saying about what happens when you make assumptions, and Ulrich says we should never make assumptions about F.P. "I always talk to Roberto about it, you know, this sort of through line of his, being sometimes good people do bad things for the right reasons. But as far as who's pulling the strings, I don't think he's fully aware of all of it."

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We'll eventually find out everyone's dirty secrets, and that goes for the parents, too: "One of the nice things -- and it wasn't intentional -- but the idea that [the parents] all went to high school together, you know, was kind of in the pilot," says Aguirre-Sacasa. "And I just ... almost arbitrarily decided oh yeah, they all went to Riverdale High. And then what we realized is, 'Oh this is great! They're a shared history and they know secrets about each other that their kids don't know.' You know, for instance, in the dinner party scene, F.P. seems to know something about Alice and Hal that Betty doesn't know.

Part of the DNA of the show is to reveal these secrets and there [are] still some huge ones, huge secrets to come in the last two or three [episodes]. [They're] kind of game-changing secrets, I would say. So that's part of the fun of it. ... For instance, when we were bringing Mary in, one of the nice things was, 'Oh my god, they all know each other!' They all went to high school so it's sort of like you could immediately get into a story with them. But yeah, it's nice that the parents have secrets that the kids don't know about and the kids don't know their parents as well. There's more of that in the last, kind of in the stretch from [Episode] 11 through, 11, 12, 13 and it just kind of gets deeper and deeper into the swamp of secrets."

Riverdale airs Thursdays at 9/8c on The CW.

(Full disclosure: TVGuide.com is owned by CBS, one of The CW's parent companies.)