From left: Neel Brown, Sam Guthridge, Tom Lyons, John Seebach and Stefan Custodi. (Jame Anderson)

A few months ago, Only Lonesome played a gig so sparsely attended that the local bluegrass quintet’s name felt a little too apt. The group has a scorching reputation, but nobody had shown up to listen, and the band’s banjo player, Sam Guthridge, thinks he knows why: “We forgot to promote it.”

Whoops. But that’s the way it goes when you’re playing old-school bluegrass in an all-about-the-music kind of band, and sometimes, that managerial aloofness can start to feel like a kind of armor. “We don’t want to take things too seriously,” Guthridge says. “I think we’re afraid we’d knock the sparkle out of playing together if we started doing photo shoots with those umbrellas and the big lights.”

Which means that Only Lonesome’s only real ambition is to play a propulsive, tough-minded, urban bluegrass — a style that used to thrive in the District and Baltimore way back in the 1950s.

The group’s members — guitarist Neel Brown, bassist Stefan Custodi, fiddler Tom Lyons and mandolin player John Seebach — are too young to have lived through that era, but, Guthridge says, he and his bandmates have learned plenty from the surviving musicians of that scene, and they all think of this music as a living, breathing, sweating, bleeding thing. “We’re not putting [the sound] in a museum,” he says. “It has an energy and a vibrancy.”

True. Just don’t come to an Only Lonesome show expecting a blast of Appalachian sunbeams. “The songs are sort of darker,” Guthridge says. “And that’s really where the name Only Lonesome comes in — we’re doing the lonesome stuff. We’re not doing the pristine thing. We want to play music with some hair on it.”

Show: Dec. 7 at 8 p.m. at Mr. Henry’s. mrhenrysdc.com. Free with $12 minimum on food and drink.