In “National Anthem,” Charlie Plummer’s resilient Dylan is 21 and eager to be free.

Raised without a father and a partying, often absent mother, Dylan has spent his life watching over his little brother while he works as a day laborer.

Everything changes when Dylan, who is straight, is hired to work on a ranch populated by gay men, drag queens and lesbians.

“When we stumble on him, he’s more or less at a crossroads internally for himself” Plummer, 25, said.

“I don’t think he sees himself as someone who should feel sorry for himself at all. But that personal question of, ‘Should I give up on this part of myself?’ That’s a real question so many people face. In his case it’s equally having to do with daily pressures as it is to do with just the reality of the circumstances.

“That was really clear from the beginning. Knowing that what we see over the course of the film is this real, physical, emotional transformation that this guy is able to undergo. It leaves him feeling a lot more full and open about himself by the end.”

Comfortable being straight, he embraces this benevolent queer society.

“It’s definitely true that Dylan would identify himself as straight going into what our story is, he wouldn’t even really question that,” Plummer said.

“I think, quite honestly, as he’s connecting with this group, he probably has pretty similar feelings about himself. It’s only over the course of the film that his own definition of what that means for him starts to expand.

“But it really is just an expansion. I don’t really see it as, ‘He was one thing and then was another.’ It was more this natural evolution that, thankfully, these other folks came into contact with him at the right time to pull him into that place.”

Plummer was convinced to take this dive by writer-director Luke Gilford, the son of an award-winning rodeo champion. Gilford is making his directing debut based on his monograph, “National Anthem: America’s Queer Rodeo” which documented the queer rodeo and members of the International Gay Rodeo Association (IGRA).

As Dylan, the outsider, becomes interested and accepted, he profoundly changes.

“Pretty clearly,” Plummer said, “there’s a radical acceptance that he comes into contact within that community that completely changes how he views himself, how he views the people he loves, and how he views his future and what’s possible.

“And not just as far as his identity, but as far as his journey, his experiences. It’s impossible to put into words, but it’s very clearly a feeling that is the fuel to send him on the rest of his life.”

“National Anthem” is in theaters July 18