[WARNING: The following story contains spoilers about Wednesday's episode of Criminal Minds. Read at your own risk.]

Ay dios mio, Reid.

The BAU's resident genius is in a whole lot of trouble now, after he gets arrested on Wednesday's Criminal Minds for cocaine and heroin possession following a high-speed car chase through a Mexican desert. It turns out Reid (Matthew Gray Gubler) had been making trips below the border on the D-L to score experimental drugs for his mom (Jane Lynch) — hence those vials from two weeks ago — from a doctor named Rosa Medina (Ani Sava).

Too bad that's not the worst of it. Rosa has been stabbed to death in the motel room where she and Reid met for their transaction. In a cruel twist of fate for a dude with eidetic memory, Reid was drugged — likely by Mr. Scratch (Bodhi Elfman) — and can't remember all the details except for a third person being in the room and at one point holding the knife himself, so he gets charged with her murder. With some help from Criminal Minds: Beyond Borders' Simmons (Daniel Henney) and Clara (Alana de la Garza), the BAU figures out that Rosa is actually an American citizen, so Reid gets extradited back to the U.S. for his arraignment. But because he never disclosed the trip and wasn't in Mexico on government business, he's not eligible for the FBI's top-notch legal counsel.

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The episode, co-written by showrunner and executive producer Erica Messer and Kirsten Vangsness, kicks off the long-teased serialized arc for the back nine episodes of the season that will be music to the ears of Reid die-hards (except for whole "murder suspect" of it all). "Reid fans will definitely get their fix in these episodes," Messer says. "There will be a lot of Reid and a really great story."

See what else Messer had to say about crafting the arc and what's ahead.

When did you come up with this arc?
Erica Messer:
About a year ago we came up with the arc. It was on the heels of Shemar [Moore] leaving. Matthew, Kirsten and I had been working together on that episode and we were talking about what Season 12 could look like. I started kicking around this idea and pitched it to Matthew and he really loved it. So I pursued it and then we got all the other writers involved and we came up with the back nine for this entire season that will dive deeper into Spencer Reid.

This never changed with everything that happened in the past six months?
Messer: That was the thing — this was always our trajectory for Season 12, doing a serialized arc. It's such a different way for us to go. Despite all the other stuff that happened this season, that never faltered.

This had to be a Reid story, but do you think if you and Matthew hadn't been working together on Shemar's last episode that you might've come up with something else or used someone else as the focus for a similar arc?
Messer:
Matthew has been on the show all 12 years and was looking for challenges, and creatively as storytellers, we all are, and it felt like by Season 12 we've earned the right. I think our fans crave for when we dive deeper into our characters. It all seemed to be happening at the same time. Matthew was the perfect character for this. Fingers were crossed we'd get Jane Lynch and we did, which was really imperative, given the direction this arc is going, and to show the only thing that would ever make Reid do anything this risky was if he thought it would help his mom.

How would you have adapted it if you couldn't get Jane back?
Messer: It would've still been that story. Mom would've just been offscreen instead of her coming back in Episode 11 and they had that great play in the apartment. The slap — I mean, jeez! But it wouldn't have been as impactful. Once we knew we had Jane, things got better and better. We were able to break Episode 11 with her in it and set up what his struggles have been with trying to help his mom. The vials came into play and all of that. If we hadn't had her, it would've been a bummer, but at the same time, it didn't falter our stories. We knew we were going to do this arc and that was going to happen no matter what.

I like how bittersweet it is because you know how much he loves her and wants to help her, and it's that tragic notion of "you can do anything you put your mind to," and he has always been able to solve everything, but he can't solve this.
Messer:
Isn't that the heartbreak of it? It's heartbreaking. I love it. It feels relatable in a way for people who have loved ones who are suffering and can't do anything to help them or they do everything they can to help, but it might not be solvable.

And he always looks at things so logically, but his judgment is clouded by his need to help.
Messer:
Yeah, I think that is accurate. It's that thing of, "You're too close to the case." The case here is mom. By all means, he's going to do that and it's led him down this unexpected, crazy path. He says to everybody at the end of the episode, "I should've let you know." And they say, "You're not alone in this anymore. You can tell us anything." The sucker-punch is that he doesn't remember anything else because he was drugged while he was down there. It's that unfortunate mystery that we'll solve by the end of the season.

Do you think he's finally accepted that he might not be able to cure her Alzheimer's or is he still too stubborn?
Messer:
I think he's going to realize that it's going to take a village to keep mom healthy and safe.

Matthew Gray Gubler, Criminal MindsMatthew Gray Gubler, Criminal Minds



Is Mr. Scratch the one who drugged him or ordered someone to drug him?
Messer:
We're certainly pursuing that path. That's the most logical person to be involved in this, especially given our history just this season with Scratch. He will be a big player in the back nine.

When will we see him strike again?
Messer:
It's all sort of us unfolding over the season. ... The goal for us is we want all eyeballs on this story. It's such a challenge and a different thing for us to do. We're really curious. I don't think fans will be able to turn away with sweet Dr. Reid in this kind of jeopardy.

It seems like Rosa knew whoever the killer was. Can you confirm that?
Messer:
That will be part of a second round of cognitive interviews in a couple of episodes. That will pay off. Did she know that intruder or did she not? That will be something we dive into deeper.

What's Reid's next move? He's not eligible for the FBI's legal assistance. Who do they hire?
Messer:
Doesn't that totally stink? I thought, "Oh, this will be fun. We'll be able to play that." But our research on the reality [told us] actually, no, he wouldn't be able to get help. So it plays into our story really well. The reality helped us out here. In next week's episode, Prentiss will introduce him to an old friend of hers who's an incredible defense attorney, Fiona Duncan (Jeananne Goossen). She will be with us for a number of episodes as Reid's attorney, trying to get him out of this mess.

Is he going to be out on bail? Is this going to trial?
Messer:
The big question in next week's episode is, will he plead guilty or not guilty, and what would that mean? Will he be out on bail until there's a trial? I don't wanna tease what even happens there because it's such a strong episode and it's such an interesting moral dilemma. How could he plead guilty to something he has no clear memory of? His moral code says he never would've done that. And his FBI agent side is like, don't admit to something you didn't do. And yet if he does that, he'll get a lighter sentence and all that stuff. Do you make that deal with the devil? Or do you take your chances on being proven innocent? It's a really great episode.

Is this arc going to last through the complete rest of the season or will it wrap up an episode or two before the finale?
Messer:
It pretty much takes us into Episodes 21 and 22, which will kind of act as a two-part finale. This dilemma of Reid's will get heightened every week until we get to the end of the season.

What lengths will the BAU go to to prove Reid is innocent?
Messer:
They will basically do everything in their power. Nobody wants to do anything that would cause the BAU to get investigated, but at the same time, some characters make some choices that maybe they've never had to make before. Or if caught, they would say, "I did it that and I would do it again if it meant I would save my friend." It kind of allows the entire team to look at their actions differently because one of their own is in trouble?

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Does that mean Prentiss' (Paget Brewster) lie about the recording will come back to haunt her?
Messer:
It does. I feel like she would do anything in her power at that moment to get him out of that Mexican prison. He was going to get transferred to a really bad place. I'm cheering her on when she says, "I never recorded it." I'm like, "Yeah, you tell him!" [Laughs] But that's also technically not OK. It's that fuzzy gray area of, what would you do? I think we all think we would play it on the up and up, but the reality is a lot messier.

Does she actually delete it eventually or is it still on her phone?
Messer:
You'll have to wait and see!

Does Reid getting drugged stir any PTSD? We get some flashbacks to Hankel.
Messer:
I really wanted to play it in that moment of "somebody did this to me before" and the PTSD of that. Ultimately, as we get into later episodes and fingers crossed that we get into Season 13, that would be a very real thing that we can play. He was in that scenario because he made some bad decisions, but ultimately he was victimized in all of that. I think he would have to take stock in his whole backstory.

When does Jane return?
Messer:
She'll be in Episode 19 and again in 22.

The finale. Is there a happy ending for this arc?
Messer:
[Laughs] Again, this is the fun of doing a serialized arc on this show. You have to tune in and see! It will continue to be this bittersweet scenario even though it's in this incredibly dangerous surrounding. But at the same time, every time you look at Reid, you see he was just trying to do the right thing for his mom. That is at the foundation of this whole story. It's like you're cheering on this hero because he did something you might do to help a loved one and because he's an FBI agent and because there's a crazy psychopath targeting his team and because we're a TV show, stuff went super sideways.

Criminal Minds airs Wednesdays at 9/8c on CBS.

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