In most of your book musicals, Act 1 ends when the story has crested in conflict, tension, and suspense. If our heroine is pouring out her heart downstage while her dastardly two-timing lover is slow dancing with the other woman upstage behind a transparent scrim, we expect a spotlight shining down boldly on the cad’s infidelity.

Written and designed by James Vita for Actors Scene Unseen, Crystal Ballroom: The Musical flouts both of these conventions. Attempting to do for English composer Joe Jackson what Catherine Johnson did for the ABBA songbook, Vita creates a dance studio in Memphis that fields a ballroom dance team — comprised of students, teachers, and professionals — to vie for medals in London at a swank international competition. Embedded in this storyline is a narrating filmmaker, a cluster of romantic triangles, a military marriage on the brink, and a couple of hidden identities.

That’s an ambitious agenda for even a seasoned book writer, but when Vita decided that his scenario would ferry us to 28 different songs — compared to a mere 22 in Mamma Mia! — it should have been clear to somebody that he was biting off more than he could chew. Development is painfully lagging on all fronts when we land in London, yet Vita leisurely stops the action to celebrate the arrival with two songs, “Nineteen Forever” and “Memphis” — one more catchy and irrelevant than the other. About the only suspense Vita has conjured up until now, when he abruptly brings the curtain down at Booth Playhouse for intermission, is whether there will be any drama when we return.

Actually, the same lighting gaffe occurred twice in Act 2 as the womanizing Gregory, a surprisingly good Michael Harris in his Charlotte musical debut, dances with two of the studio instructors. The first jealousy-inducing slow dance is with Sharon (Caryn Crye), whom fellow student Matthew (Daniel Gallagher) has his eye on but cannot seem to approach. Later on, when we are well past the point where most of the plot complications should have been resolved, Gregory takes a turn with Alicia (Lisa Yarbrough), a more willing and wanton instructor — a liaison that sparks the jealousy of Alicia’s smooth-stepping boyfriend (Jermaine Coles) and Gregory’s wife (Cindy Dozier).

We can see Gallagher’s and Dozier’s sufferings plainly enough as Harris dances, but because the light streamed down on the scrim so garishly, we could hardly see Harris and his multiple turpitudes at all. Sitting beside me, my wife Sue had a slightly better angle and confirmed what I suspected when Harris emerged from the wings a few minutes later rubbing his chin: that last dance had climaxed with Alicia slapping Greg in the face after the letch had made some lewd advances. It was invisible where I was sitting.

Now Vita was notably adroit in his set design, video design, and lighting in Unseen’s previous project, the Turn of the Screw at Spirit Square in April 2010. So the spotlight snafus that plagued Crystal Ballroom on opening night may have been the result of his attentions being diverted elsewhere. After those spotlights didn’t shine on Harris and his partners, a whole bank of lights swooped down toward the stage and did absolutely nothing before disappearing back into the flyloft, bolstering my theory of pilot error.

If Vita’s script and technical polish remained in an embryonic state, Jackson’s music emerged decisively as worthy of celebration — and the four-piece band led upstage by Alan Kaufman proved to be worthy celebrants. Candace Jennings worked choreographic wonders with a cast that only sported spotty ballroom aptitude, let alone championship grace. Yarbrough and Coles were clearly the slickest couple with their floor work, though Yarborough’s vocals gave her a slight edge as a triple threat.

Matt Carlson, who starred as Radames in the Northwest School of the Arts production of Disney’s Aïda just 30 months ago at the Booth, was a superb choice for our filmmaker narrator, Luke, nailing every one of his vocals. As the corrupt and dissolute studio chief, Miguel, Kaio DeSouza enlarged upon the splash he made in The Wrestling Season last December, showing that he has singing and dancing gifts to complement his acting chops. DeSouza was a little young for that sort of position — and to be paired with Crye as his girlfriend Sharon — but that casting glitch didn’t compromise how well they looked and sounded.

Cynthia Farbman Harris rebottled some of the Maria Callas arrogance she brought to Master Class two years ago for her role as Valentina, the Sarajevo-born diva of the ballroom team, making up with sheer chutzpah what she lacked in dancing finesse — and much the same can be said of husband Michael’s singing as Gregory. Steven B. Martin as an abrasive, shell-shocked Afghanistan war vet was effectively paired with Kara M. Martin as his preternaturally indulgent wife, though Vita commits another rookie mistake here by planting two alcoholics in the same script.

Stylistically, Elizabeth Peterson-Vita gets the tone and spirit right, but she isn’t always sufficiently demanding. There are definitely weak links as we get deeper into the casting, and the problem is compounded when those inexperienced hands aren’t drilled on how to behave when you don’t know what you’re doing: if it’s in the middle of a busy dance routine, for instance, you don’t just stand there stock-still. And if your husband has written a script that tries too much, meanders in its development, and clocks in at 136 minutes plus intermission, you tell him that songs need to disappear and that stories need to be trimmed, tightened, and punched up.

Otherwise, he has the unpleasant experience of reading it here.