[AMERICAN GOTHIC] Derrick Martin and Chelsea Campbell live a classic Portlandian fairy tale. A pretty, small-town girl leaves Washington to become a big-city barista. She meets a music nerd with a caffeine habit. A few years later, the 25-year-old proposes to her man and they walk toward the sunset, guitar and banjo at their sides.

But as the core members of swamp-stomp folk army St. Frankie Lee, the chipper couple offers twangy ballads that evoke Natural Born Killers more often than Cinderella. Set to the steady thud of a stand-up bass and Martin’s sparse banjo plucking, St. Frankie offers up enough cold-blooded violence and kinky sex to make Freud’s cigar explode.

“We’re storytellers, and it’s fun to tap into this darker side,” Campbell says. “My favorite songs are the nasty ones. The skaaaanky ones.”

St. Frankie Lee trudges toward a fiery apocalypse, with Campbell wailing like a possessed June Carter Cash as she trades vocal calls-and-responses with Martin, who comes across like a Southern preacher. With four bandmates tinkering on everything from accordion to theremin, the group’s execution is clean but rugged. Harmonies skewer off-kilter as the pair croons about death and destruction, fucking and fighting, smattering the tunes with the witty wordplay of storytellers raised on Washington Irving.

“Stole from me last week/ You can bury me with everything/ To him it’s all been solved,” Campbell croons on “The River,” a ghostly, kinky song dealing with fetishized theft and kidnapping gone horribly awry. “Hangman in polished boots/ Silver stakes in his hands/You won’t walk away.”

St. Frankie Lee’s 11-song debut, Let’s Get it On, crawls through the jagged underbelly of Americana, and it bears scars. The self-produced gem hammers home an unrefined honesty absent in like-minded groups that try to polish a sound that’s rusty by nature.

The band is a walking contradiction that would give Kris Kristofferson pause: Its two lovebirds lock eyes while harmonizing lines like “I’ll kill you, you bitch.” Then they bust into a folksy rendition of Justin Timberlake’s “Cry Me a River.” Let’s just hope the glint in their eyes is true love rather than repressed psychosis.