It's the story of Tracy Turnblad (played by newcomer Nikki Blonsky), an energetic fireplug who's four-foot-six in every direction. As a teen in Waters' hometown of Baltimore, circa 1962, Tracy lives for her after-school TV dance show, "The Corny Collins Show." She tries to audition for the show, but her love of "race music" - R&B - gets her rejected by the racist station manager, Velma Von Tussel (Michelle Pfeiffer).

But when Corny himself (James Marsden) emcees her school's sock hop, Tracy impresses with her dance moves - sparking an on-air love triangle among Tracy, the show's scream-inducing heartthrob Link Larkin (Zac Efron, from "High School Musical") and the show's reigning queen, Velma's daughter Amber (Brittany Snow). But when Velma cancels Corny's monthly "Negro Day," the only day Baltimore's black kids can dance on TV, Tracy becomes determined, with support from record-shop owner Motormouth Maybelle (Queen Latifah), to integrate the airwaves.

Unlike Waters' version (still the trash king's best movie), the musical splits its time between Tracy and her mother, Edna (Travolta), a dumpy hausfrau who hasn't moved her size 56-DDD body out of the house since 1951. Encouraged by Tracy and by her lovingly dotty husband Wilbur (Christopher Walken), Edna ventures out to discover the brave new world of the '60s in all its bouffant glory.

Shankman, a choreographer before becoming a director of lightweight comedies ("The Pacifier," "Bringing Down the House"), focuses his energy on the sprightly dance numbers. But he skimps on the technical side, leaving the first half as flat visually as your average sitcom.

But near the movie's midpoint, some things happen to rescue "Hairspray" from being a two-hour tease. The Tony-winning songs, by Marc Shaiman ("South Park: Bigger, Longer and Uncut") and Scott Wittman, start to move you. The supporting players - notably Amanda Bynes as Tracy's wallflower pal Penny and Elijah Kenney ("Take the Lead") as Maybelle's dance-loving son Seaweed - come into their own.

Most importantly, Travolta gets comfortable in his borrowed skin and makes Edna less a caricature and more human, particularly in "(You're) Timeless to Me," a comically romantic dance with Walken. Travolta, though he's having his best song-and-dance moments since "Grease," still isn't the force of nature that was Harris Glen Milstead, aka Divine, the original Edna. (Divine, unlike Travolta, would have kissed Walken on the mouth.)

By the glorious finale, "Hairspray" wins us over with its warm-hearted message and rump-shaking music. The final song is called "You Can't Stop the Beat" - and after a chorus or two, you know it's true.

SEAN P. MEANS can be reached at movies@sltrib.com or 801-257-8602. Send comments about this review to livingeditor@sltrib.com.