The co-author’s story rooted in the California Gold Rush is en route to becoming “a properly staged musical.” (Stacie Huckeba/Handout image)

“Hangtown Dancehall,” which will have its local debut Friday at the Birchmere, began as a single tune. Then, explains co-author Eric Brace, it grew into a song cycle. Now it’s a “folk opera,” well on its way to becoming a full-blown musical.

Brace has lived in Nashville for more than a decade, but before that he was a Washingtonian — and a Washington Post staff writer. In fact, “Hangtown Dancehall” is rooted in a story the singer-songwriter penned for the paper’s Travel section in 1999. It chronicled a trip to Placerville, Calif., where Brace was born and lived until he was 7. For a time in the mid-19th century, his birthplace was called “Hangtown” because justice there so often involved a noose.

“Since I was born up in Gold Rush country,” he says, “I was always aware of the mythology of the Gold Rush, but never really aware of any of the historical facts. So when I wrote a travel story about the Forty-Niners, I did some real research. I finally got up to speed on what really happened.”

The onset of gold fever, Brace argues, “marked a time in American history where you throw out the Protestant work ethic and decide that it was every man for himself. We’re all greedy and we’re going to get rich quick. I think it defines whatever the character of modern America is more than any other event. More than the Civil War and industrialization.”

Clearly, that’s more thematic luggage than one song can carry.

Eric Brace, left, and Karl Straub. (Michael S. Williamson/TWP )

The project actually started with two tunes, only one of which Brace and co-composer Karl Straub wrote. First came “Sweet Betsy from Pike,” a folk standard about a couple that travels from Missouri to California. It takes 15 verses for Ike and Betsy to arrive in Gold Rush country, where they promptly break up.

“That just sparked something in me,” Brace says. “I just thought, ‘I could create this storyline about what happens after they get there.’ ”

His first song was “King Midas,” based on the life of James Marshall, who happened upon a gold nugget at Sutter’s Mill in 1848. “He’s such a classically tragic character, because he never found gold after that. He staked many claims but never found his own. People would literally follow him around. They ascribed these mystical powers to him. He turned into kind of a drunk and died at a pretty young age.”

Brace penned “King Midas” without a larger design, but began to see it as just the beginning of the tale. And, he says, “I realized that I was going to get in a little bit over my head unless I had somebody to work with. I just thought of Karl. I’ve always been a huge fan of his songwriting.”

Straub, from Alexandria, used to front the Graverobbers; his current project is the Karl Straub Combo. (Brace says the group “somehow combines Buck Owens, Thelonius Monk and the Ramones.”) Straub also did a one-album tour of duty with Brace’s Last Train Home, a band that still exists, although its leader concedes “it’s not very active at this point.”

Brace asked Straub, then studying musical composition at Howard University, to write an overture. His role soon grew. “We just started knocking ideas back and forth,” Brace says. “That’s when we decided we could collaborate on the whole thing.”

Initially, Brace recalls, “We said, ‘Should we try to pretend that we know what music back then sounded like? And do it in that style?’ We decided pretty immediately to throw out that idea. There’s no attempt at 19th-century musical verisimilitude. It’s definitely a pastiche of mostly folk styles. Folk and swing and country and bluegrass.

Eric Brace and Kelly Willis. (Stacie Huckeba/Handout image)

“It somehow holds together even though the styles kind of go all over the place. We let the theme of the song determine the direction of the music of that particular song.”

For perhaps the first time, Brace found himself pondering the work of Kurt Weill and Stephen Sondheim. “I was never passionate about musicals,” he allows. “It seemed a little too structured for me.”

But “Karl has been working with those song forms for a long time,” Brace notes. “He studied the lieder of Schubert and things like that. And I really mean studied.”

Straub sings the role of prospector Walter Brown, and Brace has the part — currently a relatively small one — of Ike. Country veteran and former Northern Virginian Kelly Willis is Betsy, who’s been given an interesting backstory.

All three will be among the 18 musicians on stage at the Birchmere; eight of the total are veterans of “Hangtown Dancehall’s” only previous live performance, last November in Nashville.

Brace admits to being a little nervous about the large ensemble, which includes horns and a string quartet. “We’re going to have a very long soundcheck,” he says. “I warned the guy at the Birchmere: I want to load in at 2 o’clock, and then I want to pretty much play the whole damn thing from top to bottom.”

Yet, he adds, “I’m truly not worried because they’re such great players.”

After Friday night, the folk opera’s immediate future is as a recording, available on Brace’s own Red Beet Records. But the musician is working on its next incarnation.

“It is not yet a musical where characters talk,” Brace says, which is why at the Birchmere local arts-radio personality Robert Aubry Davis will provide brief narration between the numbers. But the composers are working on a script and additional songs to fill in what Brace calls “some holes in the story.”

He thinks “Hangtown Dancehall” will be “a properly staged musical someday,” and as part of their ongoing education in the genre, he and Straub have gone to see many examples. “We’re stealing ideas left and right,” Brace says.

Jenkins is a freelance writer.

Hangtown Dancehall — 7:30 p.m. Friday at the Birchmere, 3701 Mt. Vernon Ave, Alexandria. 703-549-7500; www.birchmere.com