Theater fans who love a good yarn could only be disappointed by the skeletal tale at the heart of the Broadway musical "Mamma Mia!" The characters are sketchy. The plot is dopey. But the fabulous score, a lushly orchestrated cavalcade of hits by 1970s Swedish pop rockers Abba, makes the long-running show an irresistible delight.

The new film adaptation starring Meryl Streep, Pierce Brosnan and Colin Firth had the potential to address the musical's flaws. It takes mere moments on film to create intimacy between characters, to show with a glance the depth of emotion that on stage can take several scenes to demonstrate.

But screenwriter Catherine Johnson and director Phyllida Lloyd -- the same team who created the stage version -- are big-screen novices and take only partial advantage of its strengths. The result is fun summer fluff, particularly for middle-aged women, but no more satisfying than cotton candy.

Lloyd cast the main roles well. Streep plays Donna, a former pop singer who slept around in her heyday and got pregnant by one of three men: Sam (Brosnan), Harry (Firth) or Bill (Stellan Skarsgard).

Her daughter, Sophie (Amanda Seyfried), is about to marry. Having found Donna's old diary, which reveals her three potential fathers, Sophie invites them all to Donna's Greek island resort for the wedding, signing the invitations with her mother's name.

The core quintet interact nicely, with Streep and Seyfried displaying an enviable mother-daughter bond and the men forming a motley but amicable trio.

Donna's two old friends and former bandmates are also fantastic -- both veterans of Broadway, TV and film, and it shows. Christine Baranski plays the surgically and chemically enhanced divorcee Tanya. Julie Walters (Molly Weasley in the "Harry Potter" film series) plays Rosie, a cookbook writer. Donna and her duo are the film's strongest suit: sassy, funny, fallible women who are content with themselves even when they're not getting what they want.

Though Sophie has little apparent chemistry with her fiancé, Sky (Dominic Cooper), their scenes together are mercifully brief.

Film's capacity for larger casts allows for an enormous chorus of island workers and neighbors. This makes for a rollicking parade in "Dancing Queen," a fantasy scene in "Money, Money, Money" and other elaborate numbers. And Donna is ever surrounded by a modern-day version of a classical Greek chorus. The scenery is also gorgeous.

If you're seeking aural bliss, you'd be better off seeing the musical, which has a far superior sound. Baranski and Seyfried sing well, but the others were clearly cast more for their other talents. That said, it's touching to see Brosnan struggle through his lyrics, his voice on key but strained. And Streep's plain voice frequently conveys poignant emotion in a way that a prettier voice may not.

The film's lame dialogue and flimsy characterizations are less excusable. Johnson should have omitted a few tunes (the song lists differ a bit anyway) and used that time to flesh out the story and characters. And Lloyd should have used film's microscopic perspective more to her characters' advantage.

If Hollywood persists in playing "Gimme! Gimme! Gimme!" with Broadway's cash cows -- "Phantom," "Rent," etc. -- it ought to get a better grasp of the strengths of each medium. As it is, "Mamma Mia!" remains Broadway's baby.