Ketch and Critter, aka Ketch Secor and Critter Fuqua, are founding members of the band Old Crow Medicine Show. Their Reunion Tour, which will see them today in Charleston for Spoleto, is two friends doing what they’ve always done best for more than 20 years: exploring the music and exploring the past.

Joined on this tour by Old Crow Medicine Show bassist Morgan Jahnig, the power trio gets back to the origins of one of folk music’s most compelling acts over the past decade or so.

Every band has its origin story: at school, in a Liverpudlian club, in a Seattle garage, on a radio broadcast. Old Crow Medicine Show tells of busking across Canada and back to Boone, N.C., all the while honing its craft, learning how to feel a crowd and work it.

There’s a lot of that early energy and intensity in a Ketch and Critter show. It’s scaled-back, but high-powered American music. Some of the labels used to describe their music didn’t even exist when they got started: folk, alt country, down-home acoustic, old timey, retro-roots, Southern.

Critter doesn’t care for labels beyond American: They play the music they do because it just feels right, music making is a visceral experience.

The stripped-down format allows Ketch and Critter to explore new genres, such as South Texas conjunto with its accordion and bajo-sexto. They also play tunes penned when they were getting started, ages 12 or 13, in Virginia, listening to Hendrix, Dylan, Nirvana and Guns N’ Roses. And there’ll be music from the Route 11 Boys, their band in the mid-1990s.

Ketch and Critter have rediscovered the joy of playing together professionally after a hiatus of four years. They’re talking about making an album. Southerners, they’re excited to be back in Charleston, where Ketch has fond memories of Spoleto and where Critter’s twin brother was a tour guide downtown for a time.

Says Critter, “Ketch and Critter Reunion will be different from a Crow’s show: There’ll be more talking; we’ll lapse into the normal rhythm of our friendship; our friendship will come out on stage.”

The audience is in for a rare treat.