Based on the iconic DC Comics story of the same name, “Crisis” unfolds over five episodes and yes, he reached out to Nic Cage to star.

On Sunday, December 8, The CW kicks off its latest and most ambitious Arrowverse crossover event, “Crisis on Infinite Earths.” Based on the iconic DC Comics story of the same name, “Crisis” is a five-episode event, airing across the five Arrowverse series: “Arrow,” “The Flash,” “Supergirl,” “DC’s Legends of Tomorrow,” and “Batwoman.”

Featuring guest appearances and cameos from actors who have played DC characters in non-Arrowverse properties, reprising their roles—such as “Smallville’s” Clark Kent, Tom Welling, and Kevin Conroy, who voiced Batman in “Batman: The Animated Series”—the crossover will also see Cress Williams’ Black Lightning (from “Black Lightning”) join an Arrowverse crossover for the first time ever, making this officially a six-show crossover.

IndieWire spoke with Marc Guggenheim, “Arrow” and “Legends of Tomorrow” executive producer and “Crisis on Infinite Earths” showrunner, about the impending “Crisis,” from the entire production process to that Nic Cage “joke” tweet to the multiverse’s secret weapon, Beebo.

IndieWire: With the upcoming end of “Arrow” and “Crisis,” have you even been able to sleep in months?

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Guggenheim: I’ll tell you, between the end of “Arrow,” “Crisis,” and the “Arrow” backdoor pilot [“Green Arrow and the Canaries”], the answer’s no. I have not slept very much. It’s been complete insanity. But a quality problem for sure.

It’s a total of seven hours of television, which itself is almost as long as the season of a streaming show. But of course, we’re doing it in this compressed period of time of a space of three to four months. So yeah, it doesn’t leave a lot of time for sleep, unfortunately. But sleep is overrated and I’ll do it when I’m either dead or we’re finished, whichever happens to come first. Probably dead…

Obviously, “Crisis” has been teased since the first season of “The Flash,” but when exactly did you and Greg Berlanti realize that you wanted to do “Crisis” or that you would actually have the possibility of doing “Crisis,” even if it was a long shot?

Guggenheim: Well, you know, it’s funny. I actually think because it was such a long shot, it wasn’t until we got the approval from DC and Warner Bros. to even … we didn’t even know to hope for it, quite frankly. And basically it was about a year-and-a-half ago when we were working on last year’s crossover that Greg had had a meeting with the Powers That Be at Warner Bros. and DC, and they happened to mention that if we wanted to do “Crisis on Infinite Earths,” that would now be available to us.

So I would say that it was a gleam in our eye, actually, as early as “Arrow” Season One. Because in Arrow Season One, we introduced Lyla Michaels and her codename Harbinger. And Lyla Michaels is a major figure in the original comic book “Crisis on Infinite Earths.” So it actually even predates “The Flash” mention by two years.

Katie Yu/The CW

And I think, to sort of get back around to answering your question, it’s kind of indicative of the approach we’ve always taken, which is, we’ve always tried to head fake or nod to as many different corners of the DC Universe as we’ve been allowed to over the years. And most times, we’re doing it just because we think it’s a fun, cool Easter egg or a fun, cool mention. Very, very rarely do we do it with the expectation that we’ll eventually be able to pay off that tease. But it’s very nice to be able to sort of plant those little seeds and see them unexpectedly sprout over the course of eight seasons.

Like with Anatoli, who in the comics is known as KGBeast—we’ve gotten this far now and that never came to fruition. But you guys made the character work to the point that fans are pretty much okay with that too.

Guggenheim: Yeah. I think what the fans have had been really great about recognizing is that we really run the gamut. We’ve done clever little winks and nods like a pilot jacket with the name Jordan on it appearing in Coast City, which is a nod to Hal Jordan, Green Lantern. And we’ve been able to actually have Superman on the show. We’ve nodded to Themyscira, which is the homeland of Wonder Woman. We’ve done a few things. Sometimes not without raising some corporate eyebrows, but for the most part, I think DC and Warner Bros. have been very, very, very patient with us.

It’s really come a long way since the days of “Smallville,” where The WB didn’t want to lean into the expansiveness of the comic book world. Which is why you had “Birds of Prey,” despite existing because of “Smallville’s” success, not even being in the same universe. When you and Berlanti were developing “Arrow” and talking with Warner Bros., did you mention the potential for a multiverse of shows at all? Or were they not even open it to it at that point until “Arrow’s” success?

Guggenheim: You know, it’s funny. We weren’t even open to it. Our original intention when we first launched “Arrow” was to basically do one show set in a very grounded, no superpowers, no time travel, no multiple universes world. And it was about midway, maybe three-quarters of the way through “Arrow” Season 1, where “Arrow” had sort of established itself as a hit, that I think Greg sort of dared to dream of, not even a universe so much as maybe a slate of shows that could be interlinked. And just as the shows themselves have evolved, our ambitions have gotten bigger and bigger and bigger.

Katie Yu/The CW

So at this point, it seems that fans are pretty familiar with and understanding about the annual episodes where cast members have to be written out so they can work on the crossover. But could you go into detail the whole production process—from pre to post-production—for the crossovers? Especially with the added factor of Cress Williams being in on the fun now.

Guggenheim: Cress was definitely one of the trickiest pieces because the five shows that you see in the crossover, those shows all shoot in Vancouver, whereas Cress’ show “Black Lightning” films in Atlanta. So they’re basically 3,000 miles away in an entirely different country. And I’ve got to give credit to Salim Akil, Charles Holland, and Lamont Magee at “Black Lightning,” because they really moved heaven and earth to write Cress out, essentially of a week of production, which on a television show is a lot. That’s a long time. It’s like three-quarters of the episode.

And what that did was it allowed us to fly Cress on the weekends and shoot with him for the five days in the middle. And we basically worked in what we said, wall-to-wall, as much as we possibly could. And he’s able to appear in hours three and five of the crossover, and it’s much more than a cameo. It feels substantial, and it was great. Really, I don’t think the crossover would have been as satisfying as it is if “Black Lightning” the show hadn’t been represented in some way. And the fact that it’s Cress and the fact that it’s more than just one scene is really great.

Sergei Bachlakov/The CW

In terms of the start to finish of production, basically it started a year ago, a year-and-a-half ago, when we knew that “Crisis” was a possibility. And we planted several creative flags in last year’s crossover, including casting LaMonica Garrett as The Monitor. In fact, we cast him basically as a series regular across all the shows so that we could do two things. So that we could feed him in multiple appearances between last year’s crossover and this year’s crossover, but also so that he could be available to us. Because we couldn’t cast The Monitor that would then be on another show when we actually need him for “Crisis on Infinite Earths.”

And then I sort of spent a lot of time sort of thinking about things. Several months ago, I met with all the showrunners of the five shows, as well as a bunch of members of the various writing staffs, and I basically pitched them a potential structure for the crossover, where the main plot beats of each of the five hours was laid out. And my intention there was really just to create a scaffold, something that we could all discuss and workaround, and something that would also be a little bit modular so that we could adapt to the creative needs of various shows, as well as swap actors in and out.

Because like you said, one of the most challenging aspects of doing these crossovers is scheduling the actors, and I really wanted a story that sort of had maximum flexibility. And we worked for two weeks refining that scaffolding and coming up with a more detailed set of beats. Then we each retreated to our separate writing staffs and broke out the individual episodes scene-by-scene, and reconvened, figured out, “Okay, your beat really should belong in someone else’s episode.” “This scene in hour two really needs to happen in hour three,” and “This thing that’s happening in hour one and hour two, they contradict each other,” or they duplicate each other. Figuring out all those things.

Dean Buscher/The CW

Once we did that, we created these beat sheets and synopses and sent them off to our various production teams so that they could start wrapping their arms around the various production challenges. Probably the biggest thing that needed to be done was getting a jumpstart on all the custom costumes that had to be made. For example, we had The Monitor, Pariah, Harbinger, Brandon [Routh’s] Superman.

And so while they were doing that up in Vancouver, we were in Burbank—in my case, sometimes in Prague and sometimes in the Maldives—writing the scripts for the five episodes. And then we go through the scripts, we do the same process that we had done with the story beats, making sure that everything is dialed in.

I did a pass on all the steps to make sure that various things were remaining consistent, and then we start basically the normal production process, and then all the pre-production process. And again, like you said, the hardest part is scheduling. We actually have a very fun, but very low-tech procedure for how to achieve this, which is, I fly up to Vancouver and I sit in a room with the five ADs, the five assistant directors. The first assistant directors on every television show, they’re the ones responsible for scheduling. And they each generate schedules for their respective shows. And their schedules are basically what we call strips, and each strip represents a scene. And each show is designated by a certain color. For example, “Arrow” was obviously green, “Flash” is red.

And then we have a big board, which has been basically bifurcated into squares. So it represents a huge calendar. We basically shot this over the course of a month. And we take all those schedules and we cut the strips into literal strips and we basically are just moving paper around that board or moving strips from one day to another on this big calendar until all the strips are up on the board. And I always say those schedules are held together by spit, baling wire, and hope. They are an incredibly fragile thing, and the process is a little bit like doing three-dimensional chess with a Rubik’s cube. And I have to say, the ADs are incredible. They think in ways that makes the inside of my skull bleed, and in terms of what their profession is, they have to perform at an Olympic type of level to make it all happen.

And then we start shooting and we hope that people don’t get sick like they did a couple of years ago, that our weather doesn’t impact us like it did not only a couple of years ago, but also this year as well. We hope that everything works and everything comes together, and long and true, it pretty much always does, knock on wood. And then we start the post-production process and it is a process of figuring out which episodes are working, and what moments aren’t playing. Do we need any reshoots? Do we need additional visual effects to sell a moment? It’s a very labor-intensive process, but every year, by hook or by crook, we somehow make it work.

When you’re all on set for the crossover, is there any sort of mission statement or a mantra just to keep everyone from going insane?

Guggenheim: We try really hard just to be have a positive attitude and create a positive environment. But I have to say, we’ve had crossovers in years past that were a lot harder on the cast than others. And one of the things I think we’ve learned over the years is not just how to schedule this so that the schedule can tell the story, but to schedule in a way that doesn’t abuse our cast. And I think over the last couple of years, it’s been a much more positive experience for the cast and for the crew.

And my philosophy is that if you walk around with your head on fire or you’re constantly collapsing under the weight of all the pressure and the strain, then you are basically creating a toxic environment that filters down to everybody else. So we just try to maintain an upbeat disposition, and I do think one of the things that’s helped is that this is our fifth crossover, and the fact that we’ve done it four times successfully already. Even though this one is far more, just we have that institutional memory, and when moments of panic threaten to set in, we’re able to go, “Okay, you know what? We’ve been through bad times. We’ve been through challenges before. We’ve come through it. It’s worked out before, it’ll work out again now.”

Back in October you made a joke tweet about how you reached out to Nic Cage’s people about “Crisis.” But after all the other casting announcements, like Ashley Scott from “Birds of Prey,” I’m honestly not sure how much of a joke it was. Was it a joke?

Guggenheim: You know, to be honest with you, because I never want to lie on these things, that was … yeah, I actually did … we did reach out to Nic Cage.

What makes you think we didn't reach out… 😜 — Marc Guggenheim (@mguggenheim) October 1, 2019

I’ll tell you one thing, we reached out to a lot of people, and there were people who didn’t want to do it. There were people who would only do it for amounts of money that we could not ever afford. And there were other people who really wanted to do it, but couldn’t for scheduling. That was the case with a lot of, I have to say, the movie stars that we reached out to. The thing about movie stars is, they’re all shooting movies. And unless those movies are shooting in Vancouver, we’re kind of out of luck.

But I have to say that the sheer number of actors that we did end up getting exceeded my expectation.

Are there still some actors that were cast but haven’t been revealed yet?

Guggenheim: Yeah, I like how there are at least six characters who appear in the first three hours that we haven’t announced. And I’m working on even more for the last two hours. So we’ve obviously announced a bunch, but I really want the audience to be able to tune in and still be surprised. So there are surprises of sorts that we’ve managed to keep secret, and not without great difficulty, I will tell you.

With these crossovers, once they completely air, do you, Berlanti, the other writers get together and discuss what worked, what didn’t? Is there a post-mortem?

Guggenheim: Yeah, it’s funny. Over the last couple of years, we’ve ended up kind of doing that not just afterwards, but almost during the post-production process. And we inevitably … just last week I was having conversations with Greg and with Mark Pedowitz about what next year’s crossovers could look like, which is quite frankly insane. I think it’s kind of like going into a delivery room and asking the woman who’s in labor when she plans on having her next kid.

But we kind of … I think we’re crazy. I think we kind of can’t help ourselves. I can tell you right now that we have no intention of trying something this ambitious next year. I think that would be a mistake.

That would do a disservice. I hate comparison to “[Avengers:] Endgame” because we’re operating with such a much, much, much smaller budget. We’re basically producing these shows for Marvel Studios’ catering budget, and so I hate that comparison. But you look to Marvel Studios, they didn’t follow up “Endgame” with “Endgame 2,” they followed up Endgame with “Spider-Man: Far From Home” and “Black Widow.” So I think we need to really go back to the basics.

Rob Latour/Variety/Shutterstock

It’s really the end of an era with this particular crossover and with the end of “Arrow,” so that makes sense.

Guggenheim: Yes, exactly. Yeah, we’re definitely … this is an ending. And it’s right that we sort of pull back next year.

How do you hope fans feel about the crossover when all is said and done?

Guggenheim: Well, I tell you, it probably says something about my own psychology that what I tend … to just hope that people aren’t disappointed. I would hope that people would be thrilled. I would hope that people would be surprised. These crossovers are interesting because we have so many characters, we only have so much money and so much screentime. And there are some fans are inevitably going to be disappointed because you simply can’t make everyone happy.

But I feel good. I think people will be happy. I think people will be surprised about how ambitious this is, and sort of quite frankly, where the story picks up. We’re homaging this comic book story, and while we certainly have got to sort of at least reference, and in some cases, re-enact certain iconic moments, we are telling our own story. And my hope is that that story surprises people.

Understandably, everyone has been tight-lipped about what happens after “Crisis,” in the second half of the season of most of these shows. Is there anything about the future you can safely say?

Guggenheim: Hmm. I guess I could safely tell you that when I met with all the showrunners, one of the first things I said was that because of the nature of the story that we’re telling, there’s an opportunity here to introduce some major status quo shift to the various shows, if you want to do them. My job in running the crossover is not to dictate to the showrunner what to do with their end of the show, and I’m very sort of mindful about that. But what I tried to encourage was everyone to recognize that there’s an opportunity here, if they want to take it, to fix something, or introduce a new character, or introduce a new status quo shift. And the shows have embraced that.

So I think, while I can’t specifically spoil any specific change, I can say all the shows are affected coming out of it, with the arguable exception of “Legends,” simply because “Legends” didn’t come into it. Basically, the crossover launches much of that season, but I will say that the events of “Crisis” do have ramifications. Actually in one case, one rather big ramification for the “Legends” show going forward in Season Five. And in many ways, “Crisis” sets up “Legends’” fifth season. How exactly, you’ll need to watch a chunk of the season before that becomes clear. It’s not immediately clear in the first post- “Crisis“ episode. But that’s “Legends” for you, they do things a little different.

Speaking of “Legends,” with the popularity of “The Mandalorian’s” Baby Yoda, do you think that Warner Bros. will finally capitalize on the cash cow that is Beebo?

Guggenheim: I keep waiting for that. Thank you for asking the question. … Because, I don’t understand. It’s literally like, “Don’t you like money?” Like, “What is wrong with you?” I know. I don’t get it. I don’t get it. And while I will not confirm or deny whether or not Beebo makes an appearance in the crossover, Beebo is very relevant in the crossover.

Beebo is always relevant.

Guggenheim: I agree. I agree. The “Legends” offices are, especially our post-production offices, are covered in Beebo. Beebo signage, all the nameplates outside the offices are Beebos. The nameplate outside my … I have two entrances to my office, and one is “Arrow” and the other is Beebo.

One of my great … not great, but one of my most profound unused ideas is, I really want to introduce a Sheebo. I feel like Beebo needs some love.

Dean Buscher/The CW

“Crisis on Infinite Earths” airs on The CW with the following schedule: “Part One” (“Supergirl”) at 8 p.m. EST/PST on Dec. 8; “Part Two” (“Batwoman”) at 8 p.m. EST/PST on Dec. 9; “Part Three” (“The Flash”) at 8 p.m. EST/PST on Dec. 10; “Part Four” (“Arrow”) at 8 p.m. EST/PST on Jan. 14; “Part Five” (“Legends of Tomorrow”) at 9 p.m. PST/EST on Jan. 14.

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