"A Cinderella Story," a modern retelling of the classic fairy tale, is teen princess Hilary Duff's "make-or-break" motion picture. Until now, she has coasted on her endlessly cute, bubbly personality on TV's now-defunct "Lizzie Maguire," its film spin-off, 2003's "The Lizzie Maguire Movie," and in a royally annoying supporting turn in 2003's "Cheaper By the Dozen." She was acceptable in 2003's "Agent Cody Banks," but that was more Frankie Muniz's movie than her's. Could Duff make a smooth transition into stand-alone leading roles, developing a character other than her own squeaky-clean public persona? The answer, with much pleasant surprise, is yes. Hilary Duff may not be one of the most talented and polished among some of her teen peers—Lindsay Lohan (2004's "Mean Girls") could act circles around her any day of the week—but she has wisely toned down her constant peppiness for her most understated and effective performance, to date. Indeed, it is her sheer likability that breezily carries "A Cinderella Story" through a fair share of rough patches.

When she was a little girl, Samantha Montgomery (Hannah Robinson) was devastated to lose her beloved father in a Los Angeles earthquake. Now an unpopular 16-year-old high schooler with dreams of going to Princeton University, Sam (Hilary Duff) whiles away her days studying hard, waitressing at her late father's diner to earn cash for college, and answering to the every whim of her nasty stepmother, Fiona (Jennifer Coolidge), and snooty stepsisters, Brianna (Madeline Zima) and Gabriella (Andrea Avery). A possible light at the end of a dark tunnel comes in the form of an Internet penpal she forms a real connection with—someone who goes to her school and unknowingly is popular football hunk Austin Ames (Chad Michael Murray). When Sam finally meets her dream guy with a sensitive side at the Halloween dance, she undeniably falls for him. The only problem is Austin doesn't know her identity (she was wearing a mask at the time), and Sam is afraid that he will reject her when he finds out who she is.

Directed by Mark Rosman (who made the unlikely slasher film, "The House on Sorority Row," some twenty-one years ago), "A Cinderella Story" is a tried-and-true teen-comedy-cum-romance, one that doesn't win points for originality but slides by on alluring good will. The screenplay by first-timer Leigh Dunlap is a grab-bag of sharp one-liners, effortless knowledge of the teen movie formula, and, unfortunately, several lines of dialogue that clang with drippy sentimentality. Likewise, Dunlap parlays the moment of truth when Sam finally comes clean to Austin to needless lengths, bogging things down in a series of misunderstandings that could be so easily solved if Sam and Austin would just open up to each other. There are other elements that require a suspension of disbelief—that the pretty Sam would be looked at as a pariah by the popular crowd, that Austin wouldn't be able to figure out Sam's identity when the only part of her face hidden by a mask were her eyes—but these discrepancies go down easier than they should because this is, after all, supposed to be a fairy tale.

And lest it seem like "A Cinderella Story" is riddled with nothing but problems, there are a large number of unexpectedly shrewd details. What a refreshing delight, for example, that Austin quotes a poem and Sam instantly recognizes it as being by Alfred Tennyson. Sam and Austin are also developed as far more three-dimensional than most films give teenagers credit for; instead of simply being dictated by who they go to the prom with, these intelligent characters' lives involve real responsibilities, valid worries, and ambitious dreams for the future. Meanwhile, the romance that evolves between them is low-key and honest when it could have, in the wrong hands, been paper-thin. So often cinematic teen love stories are superficial, at best, occurring because the script requires them to get together rather than because there is an actual bond between them. The viewer senses that Sam and Austin are meant for each other, which makes what is at stake all the more sincerely felt.

Hilary Duff, as previously mentioned, is attractively cast and wiser than expected in her performance as the put-upon Sam Montgomery, while Chad Michael Murray (2003's "Freaky Friday") brings more soul and less of a dumb-jock feel to Austin. In the kind of priceless supporting role she has perfected, Jennifer Coolidge (2001's "Legally Blonde") is equal parts spiteful and hilarious as Sam's meanspirited stepmother, Fiona. Coolidge has fun with the part, no more so than when fearing for her life at the wheel of an out-of-control car while unable to show emotion because of her recent Botox injection. As Sam's drama-loving best friend, Carter, Dan Byrd (2000's "28 Days") gets solid screen time and some sweet moments opposite Duff. Rounding out the central cast is Regina King (2003's "Daddy Day Care"), usually typecast in nagging wife roles but given the chance here to play the virtuous, kind Rhonda—Sam's fairy godmother, of sorts.

"A Cinderella Story" has its flaws and doesn't reinvent the wheel—too many of Sam's stuck-up classmates are strictly stereotypes, for one, and where the plot is leading can be guessed a mile away—but the enchantingly romantic climax set at a football game brings things back to their genial core. And while there is an obvious "happily ever after" ending, Samantha remains realistic and mature in her narration, admitting that although she has found a great guy, there is no telling what the future may hold for their relationship. "A Cinderella Story" does amiable justice to its well-known source material while putting a pleasant spin on it. It's better than one may be lead to expect, which is perhaps the best compliment of all.