Holed up in a shotgun house in the Mississippi Delta, a legendary blues man has hung his guitar over the fireplace and sworn off the music that made him famous. The public believes Jesse “The Man” Davidson died in the car crash that killed his wife, and he is happy to let them think so.

But when a velvet-clad British rock star stops by to worship at the master’s altar, tune his dusty guitar and coax him back into the limelight for one last-chance encore, the dynamic shifts. Secrets emerge and — to the roar of stadium crowds and buzzing helicopters — something like redemption occurs.

Such is the premise of “I Just Stopped By to See the Man,” British playwright Stephen Jeffreys' charming, thoughtful and mysterious riff on musical immortality, idol worship and lost souls looking for grace. It continues on the Alliance Theatre’s Hertz Stage through April 8.

So what's the coolest thing about director Ron OJ Parson’s blues-inflected tale? The way it allows us to witness a rare and delicious moment when a singular performer inhabits a fictional character as naturally as he lives in his own skin. That actor would be Mississippi Charles Bevel, making a wonderfully understated star turn here as a man whose death has been greatly exaggerated.

Bevel is joined by Dieterich Gray (as Karl, the drugged-out, ’70s rocker dude who comes to call on Jesse) and Bakesta King (as Jesse’s troubled daughter, Della). But it’s Bevel’s show — and his character's wise, soulful presence that makes the creaky, long-winded drama such a joyful and transforming experience.

A bit shaggy and in need of a trim, the virtually plotless drama mostly stays put in Jesse’s living room. Not necessarily a bad thing, it feels as if it were written from the point of view of an outsider looking in on some exotic specimen. And by design, Jack Magaw’s nicely conceived set allows us a side view into Jesse’s cozy, shoebox-like home, where period afros and bell bottoms are de rigueur. (Costumes are by Sydney Roberts.)

Hanging everywhere over this tale is the ghost of Mississippi blues icon Robert Johnson and his mythical crossroads appointment with the devil. Karl, who may or may not be Mephistophelian, knows where to find his hero. But while Jesse is content to sit out his time in isolation, Karl and Della are desperate for deliverance.

Gray, in long tresses that make him a dead-ringer for the scandalous English personality Russell Brand, gives a lively and entertaining performance as the geeked-out rocker. Karl is fighting a drug problem and looking for a savior. In Jesse, he finds, and resurrects, his own personal Jesus. Della comes with her own set of issues, which must be dealt with and ultimately seem a little heavy-handed, as if the writer was looking for a way to dump her (and Karl) and wrap it all up. This doesn’t negate the fact that King imbues Della with an affecting touch.

Bevel’s spry blues musings are the real thing, and with Gray’s Karl coaxing him on with Jack Daniels and flattery, the night takes on a magical sheen. "I Just Stopped By to See the Man" is like a guided mystery tour of Delta blues; its many sparkling moments help smooth out the ruts.

Theater review

“I Just Stopped By to See the Man”

Grade: B

7:30 p.m. Tuesdays-Thursdays. 8 p.m. Fridays-Saturdays. 2:30 p.m. Saturdays-Sundays. 7:30 p.m. Sundays. Through April 8. $25-$35. Alliance Theatre, Hertz Stage, 1280 Peachtree St. N.E., Atlanta. 404-733-5000, alliancetheatre.org

Bottom line: An uneven but often sparkling blues mystery.