“Folk rock” isn’t that good a description these days: Many acts seem to earn the tag just by owning acoustic guitars. What’s rare is a band that actually sounds like it was plucked from a cornhusking party in the middle of Appalachia, playing songs shot through with fiddle, banjo, and ukulele. But O’Death also adds a hard, nasty edge and vocals that would be more believable coming from a gnarled, crazy old man sitting on a falling-down porch with a shotgun in his lap (or maybe Tom Waits) than from some Brooklyn hipsters. Then again, maybe their street smarts mean they can bring some mountain life to the city without anyone daring to call them hicks. O’Death performs with Rock Plaza Central at 9 p.m. at the Black Cat, 1811 14th St. NW. $10. (202) 667-7960.