The five going to town with Keith Glover's libretto and the primarily blues-based ditties that Keb Mo' and Anderson Edwards have energetically run up are Leslie Uggams, Chuck Cooper, Marva Hicks, Peter Jay Fernandez, and Michael McElroy. The almost non-stop score is molded so that all but one of these pelvis-thrusting belters gets a fiery solo. They also sing in striking combinations that get the heart pounding faster. Moreover, the creators have been so imaginative about musical expression and offbeat numbers that, at one point, Cooper and Hernandez engage in a dueling-harmonicas interlude--and they're doing their own playing. Manning other instruments and, thus, largely responsible for getting audience members bouncing in their seats are keyboardist George Caldwell, guitarists Billy Thompson and Billy "Spaceman" Patterson, drummer Toby Williams, and Anderson Edwards himself on bass.

The story, such as it is, presents Gertha Dupree (Uggams), also known as Good Sister, whose late husband, Jaguar Dupree Senior, once bested a blue-eyed shape-shifter called Marvell Thunder (Fernandez) in a guitar-playing contest. Miffed and vengeful, Thunder arrives some years later to insinuate himself into the Dupree household; here Gertha lives with daughter Glory (Hicks), who is blind as the result of a car accident. A frequent visitor to the humble household is Dregster Dupree (Cooper), twin brother to Gertha's ex-husband and now Gertha's longtime lover. Jaguar Dupree (McElroy), a prodigal son, has also returned after forfeiting one of two charmed guitars his father left him and his sister. He'd lost it in a second guitar contest that Thunder instigated. Now Thunder is knocking on the Dupree door, because he wants the second guitar. In order to take possession, he challenges Glory to yet one more face-off--but not before he has returned her sight and the two have discovered they have, er, eyes for each other.

The questions Thunder Knocking on the Door means to raise are: Will the three Duprees survive Thunder's threat? Will Marva beat Thunder in the contest and remain able to see? Will Gertha confront whatever it is that keeps her from committing to Dregster? Will Thunder, who is slowly turning to stone, be able to reverse the disastrous metamorphosis? And will Jaguar overcome the unease he apparently feels as a promising rock-and-roller to proselytize for the blues as his dad did?

But there are other questions raised by the show, if unintentionally. How factual is the connection between the Mississippi delta and the Nile delta that the authors posit as being crucial to the origins of the blues? Is the supernatural power that this connection has over the characters at all credible? Is it necessary for a man or woman to choose, as the musical implies they must, between a devotion to music-making and true romance? Actually, none of this matters: Aside from the collaborators' making a case for the blues in whatever way they can, they only seem truly interested in providing their five rambunctious characters with enough compelling conflicts and happy outcomes to sing about lustily. Maybe Glover, Keb Mo', and Anderson would like it if patrons walked away convinced that the blues have a lengthy heritage and therefore have earned the right to careful preservation. But what kind of music lover would insist on history's stamp of approval before giving in to the often doleful, often joyful feelings aroused by these kinds of songs?

It would be difficult for anyone not to think he'd gotten his money's worth when Uggams, who gets plenty of opportunity to flash that endearing smile of hers, goes sweet and lush on a love song called "Willing to Go." Hicks turns the floor red-hot with "Movin' On," a gospel-based number. McElroy swivels his hips and his voice in "Big Money," a paean to superstar success. In "Take on the Road," Cooper holds a note so long that, at the performance I attended, he was still holding it after the audience has finished applauding his stamina. In "Motor Scooter," Cooper and McElroy declare their manliness by proclaiming, "I'm a rolling stone, I'm an accident, I'm a nightmare, I'm scandalous, I'm a mountain jack, I'm a bad dream, I'm the baddest motor scooter," and the only thing wrong with this rafter-raiser is that it doesn't go on long enough. As for Fernandez, whenever it's his turn, he covers the stage with the menacing beauty of an oil slick. The figure he's portraying may not be the devil incarnate, as at first he appears to be, but what Fernandez does with him is still devilishly magnetic. All of the above have been directed by Oskar Eustis, who gives them room to strut their saucy stuff separately and together.

Toni-Leslie James hasn't been asked to fashion many costumes, but the house dresses, coveralls, and on-the-town togs that she's given the cast are right for small-town Alabamans going through all these motions in 1966. She's also provided Hicks with just the right nightgown for a hilarious one-liner that ends the first act. As the musical's title might suggest, lighting designer Natasha Katz has created a fair share of lightning, and Acme Sound Partners underline the many thundering entrances and exits. Zane Mark, Linda Twine, and George Caldwell did the arrangements and, ummm-ummm, are they good!

Thunder Knocking on the Door has gilt-edged credentials: It was commissioned by the Alabama Shakespeare Festival. The music was commissioned by Yale Repertory Theatre. The current production was produced at the Trinity Repertory Company, where Eustis is the artistic director. The show is a credit to its developers.