The cast and producers of Arrow and The Flash tease the upcoming two-night crossover event.

Ahead of a fan screening of the highly anticipated crossover, the cast and creators of the two superhero series gathered to tease what we can expect when the episodes air on December 2 and 3 for The Flash and Arrow respectively.

Though there have been some mini crossovers on both shows up until now — Oliver and Felicity have appeared on The Flash while Barry made a cameo on Arrow — the upcoming event is something else entirely.

“If there is anybody who is watching only one of the shows, [this is an opportunity] to sort of check out the other,” Arrow and The Flash executive producer Andrew Kreisberg says. “This was such a great opportunity to give the best of everything we do on both shows: it has great Arrow stunts, it has great Flash humor and heart. We’re just really excited.”

So what can we expect from the two episodes, titled “Flash vs. Arrow” and “The Brave and the Bold”?

Superhero showdown

What comic book fan doesn’t relish the chance to see superheroes go toe-to-toe? The creators on Flash and Arrow took the first opportunity to pit Barry Allen and Oliver Queen against each other, though the two are usually allies.

According to Flash star Grant Gustin, Barry will be “whammied” by a metahuman who “gets in Barry’s head.” Barry, who is determined to prove himself to the more seasoned Oliver, is “losing his mind” as a result of the metahuman attack. “Some truths come to the surface that wouldn’t have otherwise, because Barry’s been brainwashed, and that’s the reason the fight ensues,” Gustin previews.

Arrow star Stephen Amell adds, “Oliver is keenly aware of [Barry’s affliction], and they’re fighting, but it’s more Oliver trying to get him back under control.”

Crossing storylines

Interestingly, despite him being a guest on The Flash, “[t]here’s a really big character, emotional moment for Oliver on The Flash side,” Kreisberg teases. It was “set up last season and paid off in Flash, and will pay off down the road on Arrow.”

“It’s like the bomb underneath the table,” Arrow executive producer Marc Guggenheim adds, “and I think part of the fun is waiting to see when Oliver is going to learn what the audience learns on Flash. ”

Another instance of story crossover is that Felicity will come to Caitlin for help with the big mystery of Arrow‘s current season: Sara’s murder.

“There is a major step forward in the Canary mystery,” Guggenheim previews. “We have the folks at S.T.A.R. Labs in Central City, and they’re pretty scientific. They’ve got a lot of resources at their disposal, and it would be kind of a shame to not have Team Arrow lean on them a little bit to help solve this mystery.”

Diggle

Another highlight of the crossover is apparently Diggle, who is baffled by the powers of the metahumans in Central City. “Diggle has always been the guy to protect the people he loves, in a human playing field,” Arrow‘s David Ramsey explains.

“So he doesn’t know how to respond [now]. The Flash changes the playing field. We’re going to see Diggle embrace The Flash’s powers, because he’s going to come to need them” when Lyla is targeted by an A.R.G.U.S. agent out for revenge.

Lessons learned

While Team Arrow will have to face the reality of superpowers, the S.T.A.R. Labs team will have their own realities to come to terms with once they head to Starling City. “The stakes are more real than [Barry] realized,” Amell says.

“Everything in this [Flash] world with metahumans and villains with corny nicknames [is lighter]. Then they come to Starling City, and they experience a life-and-death situation … so that changes things for them a little bit.”

“It’s actually more interesting to see Cisco accept the reality that this is not a game,” Gustin adds. “In Central City, our bad guys have powers, and it’s easy to have that detachment from reality because I’m running around with lightning speed, and these guys have these other crazy powers, and we’re stopping them and putting them in our prison, essentially. Things are just a little more real in Starling, and I think that rocks Cisco a little more. It puts things in perspective for him.”

Another crossover?

Don’t expect another major crossover between the two shows for a while. “We’d absolutely love to do it again. It was very hard, but very fun. And we definitely talked about it; we have ideas,” Guggenheim says.

In the writer’s room, “everything always starts off with, ‘Wouldn’t it be cool if … ?’ A lot of [those] conversations related to the shows crossing over. And what’s really great is it looks like with the success of Flash and the success of Arrow, there will be plenty of opportunities coming our way. And we’ve got some crazy ideas. And the crazy ideas are always the most exciting ones for us.”

The Flash season 1, episode 8, “Flash vs. Arrow,” airs Tuesday, December 2 at 8:00 p.m. ET on The CW.

Arrow season 3, episode 8, “The Brave and the Bold,” airs Wednesday, December 3 at 8:00 p.m. ET on The CW.

Will you watch the ‘Flash’/’Arrow’ crossover?