Molly (Brittany Murphy) is a 22-year-old Manhattan party girl living off the inheritance she received after her mother and rock star father died in a plane crash when she was 8.

When her accountant bails with her golden nest egg, Molly must find a job and quell her extravagance. It doesn't help that she lacks a practical bone in her body.

She's propped up by the inevitable selfless friends (Marley Shelton, Donald Faison) in such films and gets an unlikely job. Molly will be nanny to Ray (Dakota Fanning), a bratty, neurotic 8-year-old whose dad lies in a coma and whose music exec mom (Heather Locklear) hardly knows her.

It's hate at first sight for neatnik Ray and messy Molly. But the film quickly turns to predictable consciousness-raising and sentimental sisterliness. Molly must learn to become a responsible adult, while Ray must lighten up and enjoy being a kid.

All this would work better if Molly truly were lovable. Though Murphy is radiant, and her laugh is infectious, her free-spiritedness is thrust in our face like a pointy object in a 3-D movie.

She's reckless and exasperating and deserving of each setback she gets.

Directed by Boaz Yakin (''Remember the Titans''), ''Girls'' is clumsily photographed, and its score is witlessly perky. In tone it lurches from nutty slapstick to soulful morbidity, and a halfhearted romance between Molly and a musician (Jesse Spencer) is a subplot played up in the ads to draw the date crowd.

Loose ends are left dangling, and the paused exclamation, ''Oh . . . my . . . God'' is repeated enough times to qualify as a mantra.

Fanning was a bright child star in the tender ''I Am Sam,'' but here she is squandered, playing one-note disdain for so long that her turnabout is unconvincing. Actors should progress along character arcs, not teleport to the other end.