University Theatre has chosen a warm show for the start of a chilly season: "Once on This Island," a Caribbean fantasy musical with a score by Stephen Flaherty and lyrics by Lynn Ahrens, set in a world in which gods are commonplace actors in human affairs, and singing and dancing is a basic part of survival.

The story itself is slight. It's a tale of love between a peasant girl, Ti Moune, and a rich heir, Daniel, and the differences in class, family and background that threaten to tear them apart. The real story is of storytelling itself, and of how tales grow and change as they're passed along.

It's warm, but not mellow. A score full of sharp harmonies and bright percussion keeps the pace swift. There's no intermission, and none is needed for the audience. But the cast might wish they had one, because it's an extremely demanding show.

The major players are part of the chorus, and vice versa; and the chorus rarely leaves the stage. An actor adds a scarf and a change of expression and switches from playing a peasant in the chorus to soloing as the goddess of love.

With the exception of some narration (also from chorus members), nearly every word of the play is sung, and sung while dancing. But the University Theatre ensemble generally handles it well, though there were occasional technical problems with sound, and some players looked a little short of breath.

No such problem for Michelle McGhee as the goddess Asaka, nor for Leigh Caudill as Ti Moune's Mama, who both have voice power and acting ability to spare. Erika Michelle Rose as Ti Moune had a more delicate sound on her ballads.

Several of the major parts will switch over to other actors during the play's second weekend. Among those remaining in their parts are David Carlton Holmes, whose strong mime skills make it hard to believe he's only a sophomore, as Tonton Julian, and Derrick L. Johnson, a powerfully voiced Agwe.

Choreographer Diane Yates-Biggs has among her studies stints with the Urban Bush Women, Ballet Folklorica Cutumba in Cuba, and the University of South Florida, which probably accounts for the graceful and evocative vocabulary of Afro-Caribbean movement that flows through the dances. Some of the chorus members express the meaning of the dances; to others, they are just gestures.

Rose's dance solo in the second part of the play is precise and well-acted. And a love song that's both sung and expressively interpreted with American Sign Language is a moving touch.

Though the loose, improvisatory style calls for minimal sets, costuming and lighting, what's there has an impact, sketching a tropical beach in golds, reds and greens with just a few abstract palm trees. The orchestra, onstage behind the actors and partially hidden, is right on time with drummers Vin Novara and Kenneth G. Schweitzer.

"Once on This Island" will be performed at 8 p.m. Thursday through Saturday at the University of Maryland, Tawes Theatre, University Boulevard and Adelphi Road, College Park. Adults $14, seniors $10, students $7. For reservations, call 301-405-2201.