"Where the Heart Is" is a shamelessly contrived melodrama with so many bizarre plot twists and tragic occurrences--desertion, child abuse, child kidnapping, a killer tornado, insanity, alcoholism, a character 's legs being cut off by a train--that it could conceivably rank up there with the ultimate of all high-pitched melodramas, "Kings Row" (1942), which also plays like a laundry list of terrible/wonderful things that can happen to characters in a small town (not to mention the fact that Ronald Reagan gets his legs cut off by a train in that film, as well).

However, the difference between "Where the Heart Is" and "Kings Row" is the acting. While "Kings Row" reaches the highest levels of absurd camp at the behest of the heated overacting (even by 1940s standards) by Robert Cummings and Ronald Reagan, the absurdity of "Where the Heart Is" is grounded in a handful of fine, nuanced performances that give credibility to what would otherwise be preposterous.

The film, which is based on the wildly popular novel by Billie Letts, charts the life of young Novalee Nation (Natalie Portman). The film covers a period of five years, during which time she transforms from a sad, low-rent pregnant teenager into a strong, self-confident young woman with enough life experiences behind her to satisfy someone five times her age. When the film opens, she is 17 years old and eight months pregnant. She and her trashy boyfriend, Willy Jack Pickens (Dylan Bruno), an aspiring country musician with a bad mullet haircut and a worse disposition, are on their way to California in a junker car he bought for $85. When they stop at a Wal-Mart in tiny Sequoia, Oklahoma, so Novalee can go to the bathroom and buy a new pair of sandals (hers fell out the hole in the car's floorboard), Willy Jack decides he doesn't want to stick around. So, he deserts her.

Having only five dollars in her pocket and nowhere else to go, Novalee holes up inside the Wal-Mart and makes it her home for six weeks until she delivers her child (who she later names Americus) on the store's floor with a little help from the local librarian, Forney (James Frain), who has an indelible crush on the young mother-to-be. Novalee is transformed into a minor celebrity--the mother of "The Wal-Mart Baby"--but the publicity doesn't do her much good. Penniless and lacking a home, she is taken in by the kindly Sister Husband (Stockard Channing) and her partner, Mr. Sprock (Richard Jones), the first in a long line of eccentric, but utterly decent small town folk who will be Novalee's saving grace.

From there, the film charts Novalee's life as she settles into life in Sequoia and surrounds herself with friends who serve the plot to either (a) help Novalee make something of her life, (b) provide a target for a bizarre, melodramatic plot turn, or (c) both. Novalee becomes good friends with Lexie Coop (Ashley Judd), the local nurse who is constantly getting pregnant (at the beginning of the film, she has four children, and by the end she has six, and they are all named after snack foods and deserts--Baby Ruth, Praline, Brownie, etc.). Lexie is, in many ways, just like Novalee--they are both beautiful and smart, but are cursed with low self-esteem and terrible taste in men. Novalee also becomes good friends with Forney the librarian, who hides his crush on her not terribly well; that romance will eventually blossom between them is a foregone conclusion. And, sandwiched in there somewhere is a helpful photographer named Moses Whitecotton (Keith David), who encourages Novalee's budding career in photography.

While all this is going on in Novalee's life, the screenplay creates a parallel plot that charts Willy Jack's life at the same time. He starts off by going to jail for picking up an underage hitchhiker who had just robbed a convenience store, but eventually makes his way to Las Vegas where he becomes a minor country star under the management of the tough-as-nails Ruth Meyers (Joan Cusack). Because Willy Jack did such a terrible thing to the film's heroine by deserting her at a Wal-Mart, he spends much of the film being punished in various ways, although the film is so good-hearted that it even allows him a hint of redemption at the end.

The film was directed by first-timer Matt Williams, whose other claim to fame is having co-created the working-class sitcom "Roseanne." Williams is an able director who elicits good performances, although he trades in the caustic humor and satire of "Roseanne" for weepy-eyed earnestness. He keeps the film moving along at a good place; the screenplay by Lowell Ganz and Babaloo Mandel covers a great deal of ground with minimal exposition. I kept dreading that they would at some point resort to reminiscent voice-over narration, but they never did.

When the film succeeds, it is largely due to the cast. Natalie Portman continues to prove that the depth she showed as a 12-year-old in "The Professional" (1994) was not a fluke. She is one of the most talented young actresses working today, and it is only her skill that makes Novalee into the kind of character on which a plot this wild could be grounded. Likewise, Ashley Judd does a nice job as Lexie, although she looks physically much more glamorous than one would imagine her actual character to be like. Well-worn supporting character actors like Stockard Channing and Joan Cusack steal every scene they're in, but not to the point of distraction.

Whether or not you like "Where the Heart Is" will depend entirely on your disposition toward melodrama and improbable plot developments. Like the tornado that rips through Sequoia midway through the film, the plot of "Where the Heart Is" tears through major developments and moves right ahead with little or no time for reflection. Many characters come and go, but the core of the film--Novalee, Lexie, and Forney--remains. At the end, you may feel either emotionally exhausted or irritated, both of which are common responses to intense melodrama. But, either way, it still doesn't quite measure up to the bar set by "Kings Row," although you can't fault it for having tried.