Not long ago, local musicians Mike Thompson and Beth Sanders of Gracious Day parked their newly purchased RV at the waterfront, made a fire, and settled in for a beautiful night. The priceless quality of the evening got the couple and songwriting duo thinking. They spent much of the night turning that feeling into a song, “The Finest Kind of Fancy,” the newest addition to the their forthcoming, as yet untitled album (due in January).

They swear that the addition of the RV changed everything. The freedom of planting their “home” wherever they feel like has led to more musical flexibility.

“The best decision I ever made was just doing it, buying the RV and going for it musically,” says Thompson. “‘Finest Kind of Fancy’ got birthed out of just sitting there and getting this feeling about how the best things are free. We’ve made more progress in six months than I made in 10 years.”

Thompson is known around town for his solo country act. He won several City Paper Best Male Vocalist readers’ pick awards a few years back. His country/rock quartet Sin County played regularly at local venues, winning Best House Band in 2007.

After a rocky stint in Nashville, Thompson returned to Charleston in 2009 and began concentrating on writing country material. He recently started performing alongside Sanders, who adds depth with piano and gorgeous harmonies, earlier this year. Thompson describes their sound as “not as folky as Gillian Welch, but Lady Antebellum is too far to the other side.”

No matter the song or the band setting, Thompson finds that Sanders has a great knack for finding second and third harmony parts.

“I think it comes from growing up around that gospel quartet style, where the third harmony was always the most intricate,” Thompson says.

Sanders has her share of singing lead as well. “My dad was a minister, and I remember loving harmonies from a really young age,” she says. “My father and uncles played together in church, and my uncle was an amazing piano player. He’s why I started taking piano lessons.”

At local shows, fans often notice their harmonies more than anything else. The texture of their singing styles is a major strength.

“I remember when I would feel like my father and uncles were off,” says Sanders, who went to high school in Sumter with country singer and good friend Lee Brice. “And my uncle would stop them and get it right. It was a relief to know that I’d been right. I was harmonizing onstage with them by age 10 or 11.”

While they perform as a duo most of the time, whenever they get the chance they lead a full band, with Ben Meyer on bass (and even more harmony), Mike Greer on drums, and Wayne Daws on electric guitar.

Thompson’s recent solo album, Falling Out of Love, is a studio collection steeped in traditional country, from swing-beat shuffles to slow-rolling ballads. Sanders performed on some of the songs as one of the many guest musicians Thompson hired. Thompson and Sanders gradually became regular writing partners and composed an album’s worth of work with an intensely collaborative approach.

“She’ll usually come up with an initial idea,” Thompson says.

Sanders interrupts her bandmate with a smile: “He says, ‘I need an idea.’ I’ll come up with one, and then he’ll make a sweet hook, and I’ll just start singing a melody.”

Gracious Day performs as a duo at the Brick downtown on Thurs. Sept. 22. They play as a full band at Bucca’s Bar and Grill in Hanahan during a fundraiser for the American Heart Association on Fri. Sept. 23. The full band plays at K.C. Mulligan’s in North Charleston on Sat. Sept. 24 as well.