A VIBRANT WORLD capital during a pivotal 20th-century uprising. A naive American newcomer stunned and then thrilled by a brash, un-Puritanical culture. Young love testing its limits, only to be interrupted when the revolution spills into the streets. Nope, that's not a description of the NC-17 "The Dreamers." It's "Dirty Dancing: Havana Nights," a movie that's barely saucy enough for its PG-13 rating.

"Havana Nights" is both a sideways sequel and a chronological prequel to 1987's "Dirty Dancing." The movie opens in 1958, five years before Jennifer Grey encountered Patrick Swayze in the Catskills. This time it's British actress Romola Garai (as sheltered but willful American high school senior Katey Miller) who meets Swayze, the dance instructor at the swank Havana beachfront hotel where the Miller family has just taken up residence. The result is not romance, however. Jane Austen-reading Katey has fallen for sexy street dancer Javier ("Y Tu Mama Tambien's" Diego Luna). After just a few spins with the passionate but honorable Javier, who works as a waiter at the hotel, Katey rejects the eminently rejectable James (Jonathan Jackson), the overbearing son of her father's boss.

In the hotel dance studio, Johnny (Swayze) whirls and lifts Katey in a quick homage to the original "Dirty," and then suggests that she enter "the big dance contest" at a local nightclub catering to upscale Americans. Helpful Katey decides that capturing the $5,000 prize will rescue her new beau's family, destitute since Javier's father was killed by Cuban dictator Batista's goons. Katey is the daughter of former ballroom dancing champs (Sela Ward and John Slattery), so she knows how to twirl, but not grind. A natural dancer who has never learned any conventional steps, Javier has the opposite proclivity. Explains Katey with gee-whiz Yankee pragmatism, "We'll mix what I know and what you know." Sounds like a winning combination, if only Castro doesn't roll into town first.

Hard as it is to believe that this scenario has any connection to reality, the movie's plot is derived from the life of the film's choreographer and co-producer, JoAnn Jansen. Her father was transferred to Havana to work for Reynolds Aluminum -- Katey's works for Ford -- and she fell in love with a Cuban dance partner just before Castro replaced Batista and Americans fled the island. Yet knowing that Katey is based on a real person doesn't make "Havana Nights" any more persuasive. The movie is still a routine Hollywood high school morality play, with snotty preppies facing the customary comeuppance at the hands of the outcasts -- who are, of course, more stylish, assured and attractive than the social underclass at any actual high school in American (and probably Cuban) history.

Despite the references to Castro and Batista, the tale's exact historical location is elusive. One momentous night soon after arriving in Havana, Katey flees the local American country club, where Sam Cooke's "You Send Me" plays, for La Rosa Negra, a sweaty nightspot favored by working-class locals. There, something strange happens: It becomes 2004. Director Guy Ferland (who made the quickly forgotten "Telling Lies in America") apparently feared that the movie's target audience wouldn't respond to vintage Afro-Cuban music, so Javier and his pals shimmy to lightly Latinized contemporary hip-hop pop by the likes of Wyclef Jean, Santana, Mya and Christina Aguilera. In this time-warped version of '50s Havana, the crowds move to chants of "represent!" -- which may be Spanglish for "you've gotta be kidding."

Actually, the movie has no sense of humor whatsoever. First love is a grave topic, of course, and "Havana Nights" was co-scripted by writer-director Boaz Yakin, whose resume includes "Remember the Titans," another glib culture-clash fairy tale. Earnest as it is, however, the film's final round of consummations and reconciliations is impossible to take seriously. "We knew this wasn't our last dance," Katey tells the audience as she heads for the States and college life. She hopes to get into Radcliffe, but clearly she's needed at Wellesley, where she could teach those "Mona Lisa Smile" girls to roll their pelvises and chant "represent!"

DIRTY DANCING: HAVANA NIGHTS (PG-13, 87 minutes) -- Includes ethnic insensitivity, an assassination attempt and lots of hip swiveling. Area theaters.

Young love blooms in 1958 Cuba, as Katey (Romola Garai) and Javier (Diego Luna) practice their moves in "Dirty Dancing: Havana Nights."