When a sleek, curvy, dark figure entered her life, Melissa Ruth knew her future would look different. She was writing songs for her second album, 2011’s Aint No Whiskey, when it came to her.

“I accidentally bought a guitar that blew my mind and changed my songwriting forever,” Ruth tells me over whiskey at The Barn Light. The guitar is a small-bodied black and brown 1958 Guild electric with a whole lotta mojo, Ruth says. “That guitar changed my life.”

The Guild helped her access a “Sam & Dave, doo-woppy” sound, which is central to the “doo-wop twang” theme of her beautifully moody and sweet new album Riding Mercury — the second album recorded with her band, Melissa Ruth & The Likely Stories. The quintet hosts a CD release party and performance Oct. 4 at the Axe & Fiddle in Cottage Grove.

Ruth defines “doo-wop twang” as drawing on the instrumental sparseness of doo-wop and the twang of country and blues. “What I love about doo-wop music is the space,” she says. “The guitar is there, but it’s not overplaying. The drums are there, but they’re not overplaying — it creates this whole landscape. I feel like that’s sort of where our music tends to go.”

In addition to Ruth’s guitar and smoky vocals, that pseudo-retro sound is teased out by blues and jazz guitarist (and Ruth’s husband) Johnny Leal, his brother, funk drummer Jimmy Leal, and bassist Scoop McGuire.

On Riding Mercury, duality exists as much in style as it does in content. When Ruth wrote the titular song three years ago, she was swinging between peaks and valleys — her mother was diagnosed with breast cancer, her school choirs were having great success at regional festivals and she was touring solo around the West.

“I guess I just wrote a song reflecting on how it’s just a big roller coaster ride,” she says. “All the tunes on the record really sort of explore that idea.” She adds, “I think that one of the things the band does really well is exist in those dual worlds at the same time.”

Ruth, who is taking a sabbatical from her day job as a K-12 music teacher in the Yoncalla school district, is touring solo (after the Oct. 4 show) with the album up and down the West coast — just her and her guitar.

Melissa Ruth & The Likely Stories host the Riding Mercury CD release show 8:30 pm Saturday, Oct. 4, at the Axe & Fiddle; $5.