‘Thunder Knocking’ Wraps Its Music in a Fable

“Thunder Knocking on the Door,” despite its ominous title, is a charming fable about magic and music that casts its own melodic spell.

Keith Glover’s story tells about an African American family in 1966 Alabama, but what it really concerns is the transformation of traditional blues into rhythm & blues, the precursor of rock ‘n’ roll.

The plot, like all tales of myth and magic, defies logic and analysis. It involves a son seeking to emulate his dead father, Jaguar Dupree, as the premier blues guitarist on the bar circuit. That honor is determined by “cutting contests”--two musicians vie until one admits defeat or is judged secondary.

Jag Jr. has just lost his last competition, and with it, his guitar, a handmade legacy from his father. To win it back, he wants to use the twin instrument left to his sister Glory, blind since a botched suicide attempt. Meanwhile, the conqueror--a mysterious conjurer named Marvell Thunder--shows up. He needs to win the matching guitar and complete his ambition to succeed Dupree as No. 1--but also to prevent losing his powers and being turned to stone.

The siblings argue about who should oppose Thunder, but, captivated by Glory’s beauty, Thunder sets the conditions. To sharpen her skills, he restores her sight for a month--and will do so permanently if she wins. Glory, likewise enchanted, falls in love with him, thus setting up a classic dilemma: Whoever wins the contest gains something crucial, but loses in love. And the problem is crystallized by Thunder singing the plaintive “Even When You Win, Sometimes You Lose.”

That’s one of several numbers in a score likely to make a popular CD. The main music and lyrics credit goes to blues Grammy winner Keb’ Mo’, with additional work provided by Glover and Anderson Edwards. Highlights include “See Through Me” and “Rainmaker,” both sweet love songs; “Believe Me,” a good retro R&B; number; and “Movin’ On,” the requisite closing hand-clapper.

Glover also directs and keeps the action involving, although judicious trims wouldn’t hurt. His sparkling cast is adept at all the musical skills, especially vocal. Best are Peter Jay Fernandez, who as Thunder shows off a mean blues harmonica, and Kevyn Morrow, whose acting and dancing make Jag Jr. particularly likable. Marva Hicks embodies Glory’s beauty, with Terry Burrell and Doug Eskew appealing as Dupree’s widow and twin brother (he’s also the occasionally corporeal Dupree).

Paul Tazewell’s costumes are exquisite, ranging from the plain garb of the period to wildly sumptuous for the magic-wielding musicians, and they are vital in Glover’s best directorial touch: Thunder’s wizardry instantly changes Glory’s red vamp dress into an elegant white gown.

David Gallo’s set neatly depicts the recurring theme of “where two roads meet” as a center-stage point that spirals into two ramps leading offstage. Kevin Adams’ lighting is generally good but includes two questionable choices: repeated eye-assaulting flashes from columns of lights as backdrop for Thunder’s stone-legged walk, and a mixed-message mosaic of reds and oranges during a blues song.

Jeff Ladman’s sound puts the music at an excessive level, but that seems unfortunately to be today’s standard.

* “Thunder Knocking on the Door,” Lowell Davies Festival Theatre, Balboa Park, San Diego. Tuesdays-Sundays, 8 p.m. Ends Aug. 14. $23-$39. (619) 239-2255. Running time: 2 hours, 40 minutes.