How 'The Flash,' many years in the works and beset by turmoil, finally reached the finish line

Ezra Miller in a scene from 'Justice League.' (Clay Enos / Warner Bros. Entertainment Inc. via AP)

There were many stressful things about making "The Flash" and getting it to theaters. It was shot in the middle of a pandemic. There was isolation from friends and family for the 138-day shoot. There were A-list schedules to coordinate for cameos. There was a star in Ezra Miller who, after it wrapped, made headlines for legal run-ins amid a mental health crisis. And behind it all, a studio undergoing leadership changes and rethinking the whole DC Comics strategy.

But first, they had to figure out how to transport a two-ton Batmobile from Los Angeles to the U.K. amid a worldwide shortage of shipping containers in 2021.

This was not just any Batmobile, mind you. It was one of the originals from the Tim Burton movies that was needed for the grand return of Michael Keaton's caped crusader after 30 years -- a major production that also involved building, from scratch, a life-size replica of the Batcave.

Director Andy Muschietti and his sister, producer Barbara Muschietti, waited nervously for its arrival worried whether it would make it in time or just be stuck in the middle of the ocean. They breathed a sigh of relief when it made it ashore, briefly celebrated and moved on to the next problem: how to get it into the Batcave at Warner Bros. Studios Leavesden. Ultimately it involved a loading it onto a modified airport cargo truck that was lifted 20 feet (6 meters) in the air and "gently rolled" onto set.

"Everything came with a little adventure," Barbara Muschietti said with a laugh in a recent interview with The Associated Press.

It's an apt if intentionally understated description of getting "The Flash" into theaters on June 16. Movie versions of the lightning quick comic book character have been in various stages of development since the late 1980s. One scenario had Ryan Reynolds starring and David S. Goyer directing; another had George Miller setting the stage for spinoffs and standalones with Adam Brody.

Then in 2014, things started taking shape as Warner Bros. plotted out a shared universe of DC Comics films, including a standalone Flash starring Miller as Barry Allen, who would first appear in "Batman v Superman: Dawn of Justice," "Suicide Squad" and "Justice League."

But even that wasn't so straightforward, with disagreements over tone and scheduling conflicts making things complicated. Several writers and directors cycled in and out of developing "The Flash," including Phil Lord and Christopher Miller, Seth Grahame-Smith, Rick Famuyiwa, Robert Zemeckis and John Francis Daley and Jonathan Goldstein, and release dates were pushed back. Ezra Miller even worked on their own treatment of a script.

The Muschiettis were finishing "It Chapter Two" when the studio approached them about "The Flash." They didn't concern themselves with the messy, marathon development history -- they just wanted to figure out if this was worth several years of their life. In the story, Andy Muschietti found a compelling emotional core: The relationship between Barry Allen and his mother, who was killed when he was a child and whom he wants to go back in time to save. "Back to the Future," which is referenced quite a bit in "The Flash," was one of their favourite movies, too. They were in.

"Birds of Prey" screenwriter Christina Hobson had taken a crack at the story and come out with something that was both fun and emotional and introduced the multiverse to the DC cannon. In Barry Allen's quest to save his mother, he accidentally gets tossed into another timeline and meets a younger, different version of himself who gets swept up in the journey. It allowed for lots of possibilities, including bringing Keaton back in a movie that also had Ben Affleck's "Zack Snyder Batman."

"We all got very excited about the prospect of having Michael Keaton come back after 30 years of not knowing what Batman was up to," Andy Muschietti said. "The multiverse allowed this to happen and combine the existing characters, the existing universe, with something that seemed to have been buried in the past."

They told Keaton, who jogged to their lunch meeting in Brentwood, they wouldn't be able to do the film without him. They wanted to find his Bruce Wayne in a place people wouldn't expect. By the end of lunch, Keaton had agreed and jogged off.

"I didn't want him to be sitting near the fireplace, like staring out of a glass of whiskey," Andy Muschietti said. "I knew he was going to transform back into Batman so I needed him to be in a place that made that transformation possible in the tradition of a reluctant hero."

Keaton's Batman was also due to make a return in the standalone "Batgirl" movie which was ultimately shelved close to completion.

"The Flash" has other nostalgic nods, including an army of cameos best left unspoiled, that helps set the stage for a "universe reboot." While making the film, big leadership changes were afoot at Warner Bros. and, specifically, DC Studios, where new co-chairs and CEOs James Gunn and Peter Safran were tasked with plotting the future of the DC Universe characters, from Superman to Batman. That new vision won't officially begin until Gunn's new Superman in 2025, but he's also said that "The Flash," though technically from a previous regime, "resets the entire DC universe."

But then during the extensive post-production on "The Flash," star Ezra Miller, also started making headlines for a string of arrests and reports of erratic behaviour last year. They were arrested twice last year in Hawaii, including for disorderly conduct and harassment at a karaoke bar. In January, they pleaded guilty to a charge stemming from a break-in and theft of alcohol at a neighbor's home in Vermont. They avoided jail time but paid a US$500 fine and got a year of probation, agreeing to abide by a number of conditions including continued mental health treatment.

Though some questioned whether "The Flash" should be shelved, the studio remained committed to releasing it on June 16 even without their star on the promotional circuit.

"We're in contact with them. They love the movie. They support the movie. And they're taking their treatment very seriously," said Barbara Muschietti of Miller. "We want everybody to see this. It's great and it's special. And it has all our hearts and guts."

While early hyperbole abounded with people like Gunn calling it one of the best superhero movies he'd ever seen, reviews have indeed been mostly very positive with lots of praise for Miller's dual roles.

"What you get is this delicious odd couple," Barbara Muschietti. "You forget that they're the same actor."

There are even rumours that the Muschiettis' DC relationship will continue with future films. But right now, the focus is "The Flash."

"Let's just wait and see," Andy Muschietti said.