In "The Nanny Diaries," the great Laura Linney takes the most reprehensible of icons, the snooty, privileged, controlling Upper East Side rhymes-with-rich, and delivers a masterpiece of Cruella De Vil-level toxin as Mrs. X. She becomes the woman you love to hate. But -- this is the greatness of Linney -- she also gives you a glimpse of the forces that crushed her into such monstrous certitude. It's funny, it's sad, it's real.

Too bad, alas, the rest of the movie isn't. Linney -- this has happened too much to her -- is once again the best thing in a movie that at most achieves a certain mediocrity. Derived from the best-selling novel of the same name by Emma McLaughlin and Nicola Kraus, it tells a fish-out-of-water story, in which its heroine, Annie, a bright Jersey college grad (Scarlett Johansson), stumbles into a job as a nanny for the rich socialite's son. No surprise, she finds the work demeaning, degrading and crushing, even as she develops a powerful affection for her young charge, Grayer. The gimmick is pale: She is by training an anthropologist, so the movie is structured as "field notes" on a "tribe" as astounding as New Zealand Maoris or South African Xhosa.

Anyhow, a couple of subplots intrude on the far more interesting Linney-Johansson relationship. One is the dynamic represented by Linney's husband, Mr. X, a slimy Wall Streeter played by Paul Giamatti. He's obsessive, withdrawn, unsupportive and a player in the worst possible meaning of that word. Then there's Annie's infatuation with "Harvard Hottie" (as per anthropology protocols, the characters are given symbolic names), played by Chris Evans.

Johansson is overwhelmed by the brilliant Linney but comes alive in an interesting way when alone with Evans or Nicholas Art, the delightful kid who plays Grayer.

Somehow the movie doesn't send you out on the high you expect. And that is: You've watched this poor if noble young woman take it on the chin for all that time. You want to see Armageddon visited upon the transgressor. That's the transaction that must close the film. But the film doesn't quite deliver. It almost does, but without giving too much away, the scene where Annie tells off Mrs. X is diluted by a variety of circumstances and filtering devices. It ends not with a bang but with a mutter.

-- Stephen Hunter (August 24, 2007)

Contains objectionable language.