Like the book it's based upon, Shopgirl is sentimental and ironic at once. Steve Martin, who wrote the novel and screenplay, mocks the superficiality of modern romance, then muses on its bittersweetness. His audience, reading or watching, can't be faulted for feeling exasperated even as they're charmed.

Martin didn't much meddle with the narrative when he translated his story from one medium to another. Mirabelle Buttersfield (Claire Danes), a 20-something aspiring artist, works as a clerk in the glove department of Saks Fifth Avenue (Neiman Marcus in the novel) in Beverly Hills. Nobody wears gloves anymore, so she spends her days daydreaming until she goes home to her dreary Silver Lake apartment, where she feeds her invisible cat (always under the bed) and works on her self-portraits.

At the Laundromat, Mirabelle meets Jeremy (Jason Schwartzman), an unkempt slacker who services music amplifiers for rock bands. They begin a desultory relationship interrupted by Ray Porter (Martin), a 50-something logician with a small fortune from writing computer code. Porter sends Mirabelle a pair of gloves purchased at her counter with an invitation to dinner. Disregarding their differences in age and status-not to mention attitudes toward relationships and fidelity-he lures her into an affair that plays out over the course of the movie, a situation resolved, in part, by Jeremy's unexpected spurt of maturity.

Despite director Anand Tucker's light touch and Barrington Pheloung's dewy score, Shopgirl hasn't the brightness of a romantic comedy nor the tristesse of melodrama. The problem is that the lovers aren't very interesting people. Ray has an appealing insouciance, an understated sophistication-he's attractive, funny and generous-but these qualities hang on him like an Armani suit. In reality, he's a cipher, sympathetic but insincere, a man incapable of commitment. Mirabelle, likewise, exudes a quiet but irresistible allure-vulnerable and guileless on the one hand, sensual and poised on the other-yet she can't achieve an identity apart from the men who impose themselves upon her, and she's too willing to trade physical intimacy for emotional comfort at the going rate-a calculus of climaxes and cuddles, dinners and gifts, with the obligatory escape clauses.

Martin knows his material, from Los Angeles' pampered rich to its penurious wannabes, and Shopgirl conveys the rhythm of the city. (The filmmakers apparently expended considerable effort assembling works by hipster artists for the film's gallery scenes.) In urban America, alas, social realism is barely distinguishable from parody. Mirabelle's coworker, Lisa Cramer (Bridgette Wilson-Sampras) is played for laughs, lampooning the Cosmo girl's guide to metrosexual bliss. But Jeremy's self-absorbed grunge aesthetic is meant to be cute as well as comic, and the movie's ending works only if we embrace his California dudeness.

Indeed, Shopgirl's plot more than once turns on notions of holistic self-improvement and therapeutic pharmacology, and it's hard to tell if Martin is being earnest or outrageous. Mirabelle, for example, takes medicine for her chemical imbalance, "a gift from God," writes Martin in the novel, "that frees her from the immobilizing depression that would otherwise surround her and seep into her body like a poisonous fog." Meanwhile, her emotionally unavailable father (Sam Bottoms), clearly part of Mirabelle's self-image problem, is a Vietnam vet whose personality dysfunction is apparently beyond the scope of modern psychiatry. As the joke goes, he's from Vermont.

Martin, Danes and Schwartzman are likeable personalities, easy to watch, well cast (obviously, in Martin's case). Refreshingly, the pairing of Porter and Mirabelle seems perfectly natural, in large part because Martin is naturally boyish, while Danes exudes a sang-froid associated with actresses from a past era. They make a good couple, except that Martin burdens them with phobias, neuroses and serotonin storms. All of which makes us long for simpler times, when misunderstandings between men and women weren't vetted by self-help gurus and analysts.

-Rex Roberts