The oldest theme in the books is: boy meets girl, boy loses girl, boy gets girl. "Stepmom" capitalizes on this but with a notable variation. Boy loses girl, boy meets girl, girl hates girl, girl likes girl. Everything else about "Stepmom" runs its course without a single mutation. In a movie that's directed and edited in a compulsively conventional manner suitable for afternoon TV, Chris Columbus helms a dramatization of a screenplay credited to five (count 'em) writers, a movie that looks every bit like one penned by a committee. Disjointed, loaded with tired expressions and disconcerting exchanges, "Stepmom" seems unable even to jerk tears from its targeted audience of women who must be as tired of disease-of-the- week pieces as the United States is of impeachment hearings.

Director Columbus has already proved his ability to deal with stories about kids ("Home Alone") and about women's issues ("Mrs. Doubtfire") but is not likely this time to approach the well-deserved box office that those features received. Exploiting a theme as ancient as those explored by Greek tragedies like "Electra," Columbus portrays the strife that overcomes a family when daddy Luke (Ed Harris) divorces mother Jackie (Susan Sarandon) and moves in with the much younger Isabel (Julia Roberts). Though Isabel knows every rock song ever played and even bribes Luke's two children with a Golden Retriever puppy, Luke's kids Anna (Jena Malone) and Ben (Liam Aiken) treat her with contempt. She is the meddler who has allegedly broken up the family, exiling the very capable and loving Jackie and putting the youngsters in the hands of a career woman who can't cook and has no experience whatever with the care and nurturing of children. If you guess that by the picture's conclusion Isabel will become a fully condoned member of the household, you're telepathic. And if you prophesy that the beloved Jackie, considered by all to be the Earth Mother herself, will suffer a recurrence of a deadly cancer, you're positively clairvoyant.

The dialogue is fatuous throughout, featuring sentences that you'd never hear in real life but have listened to all too often in movies of this sort. The women seem almost to enjoy their catfights, lashing at each other with declarations only a little more novel than 12-year-old Anna's, "I don't have to listen to you...you're not my mother." It gets even better. When the women ultimately reconcile as you vaguely suspected they would, Jackie lovingly tells her former enemy, "I have her past, and you can have her future."

There are all too many cute scenes of the whining kids, although Liam Aiken's Ben is less insufferable in his rejection of his stepmom than his adolescent sister. But performances are fine all around, with Julia Roberts looking good as a photographer of fashion models who absurdly gives up her fast-track job to be more of a mom to her future stepchildren, but it's disconcerting to watch her in a discreetly romantic bedroom scene with Ed Harris--who is in real-life seventeen years her senior and look five years beyond that. For an edgier, more mature and imaginative film about the hostility between child and dad, take in Paul Schrader's movie "Affliction," which features an Oscar-caliber performance by Nick Nolte.