'Only the Brave' trailer: Josh Brolin and Miles Teller in true-life firefighter story (exclusive)

If some of the wildfires in the new trailer for Only the Brave (in theaters Oct. 20) look real, that’s because they are. For his action-drama about the Granite Mountain hotshots, the elite firefighters who protected their Arizona community from a historically deadly fire in 2013, director Joseph Kosinski wanted as much in-camera authenticity as possible. He took footage of actual, raging wildfires near the shooting location in southern New Mexico. His crew set a few fires — small burns in wildland areas, under the supervision of local firefighters. And for close-up shots of stars Josh Brolin, Taylor Kitsch, Miles Teller, and James Badge Dale, who play the real-life hotshot heroes, he commissioned trees that could burn on command.

“We built our own forest that was lined with propane lines, so that we had a forest fire that we could basically turn on or off,” Kosinski tells Yahoo Movies, adding, “It was still hot as hell. You had to be very careful. “

Thankfully, no one was hurt on the set of the film (which also features Jeff Bridges, Jennifer Connelly, and Andie MacDowell), though they quickly learned to respect the awesome power of fire. “We were all amazed by how even flames that are 4-6 feet high, the incredible amount of heat that they put off,” says the director. “And then you start thinking about the fires that real Hotshots deal with: you know, 30, 40, 50-foot flames. And you quickly appreciate the extreme conditions that they work in every day.”

The true story that inspired the film is a sad one: In 2013, 19 members of the Granite Mountain hotshots lost their lives battling the Yarnell Hill Fire, the deadliest incident for U.S. firefighters since Sept. 11. But Only the Brave doesn’t dwell on tragedy. Instead, the film focuses on the brotherhood between the men, and the daunting heroics of the hotshots. “Basically wildland firefighters fight fires without water,” Konsinski explains. “They try to control wildfires by digging fire breaks and cutting down trees, or even setting fires themselves to back burn against wildfires. “

There are 107 hotshots crews in the U.S. — the most elite level of wildland firefighting — but the Granite Mountain hotshots are unique, in that they started as a local fire department, rather than a Forest Service team. In order to re-create the level of teamwork and expertise that these men achieved, Kosinski sent his cast into the wild for a two-week firefighter training course, taught by former Granite Mountain hotshots. When the actors returned, says the director, “Not only could I tell them to dig a line or set a back burn and they knew exactly what to do, but more importantly, there was a bond that was built, a comradery that is such an essential part of a hotshot team. And I knew it was the most important aspect to get right in making this film.” (The cast member who was most hardcore about the training? “Definitely Josh Brolin,” Kosinski says with a laugh.)

Only the Brave is a departure for Kosinski, known for effects-heavy sci-fi films TRON: Legacy and Oblivion. (He’s also attached to the upcoming Top Gun: Maverick, of which he’ll say only, “I’m very excited about the direction we’re taking it, and we’re trying to figure it out.”) Why did this film appeal to him? “ I was really drawn to the idea of, what is it that makes a certain type of person go into something that everyone else is running away from? “ he says. “And then the more I learned about who these guys were, the more fascinated I became with their story and what an incredible story it was.”

‘Only the Brave’: Watch the previously released trailer:

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