Written and directed by newcomer David Frankel, the triumph of the movie is that it pilfers from Allen without parroting him. You can immediately spot the movie's structural thievery from Hannah and Her Sisters, and the film's closing line, in which the main character attempts to sum everything up with a cute, poignant metaphor, is straight out of Annie Hall. But the picture claims its own voice because it accomplishes something Allen never could: It focuses on a female protagonist without condescending to her.

That protagonist is Gwyn (Sarah Jessica Parker), a young advertising copywriter who has just agreed, reluctantly, to marry her live-in boyfriend, Matt (Gil Bellows). Gwyn's anxieties about marriage are compounded when she discovers her mother (Mia Farrow) is having an affair, as are her father (Paul Mazursky), brother (Kevin Pollak), and, eventually, her newlywed sister (Carla Gugino). The whole world seems incapable of fidelity. How can she expect her own marriage to work out otherwise?

Gwyn's jaded journey of discovery is humorously played out as she speaks to each person and learns the reasons behind his or her wanderlust. Her dad explains his tryst with a wild (and wildly unstable) woman by stating, "At my age, sometimes you need a volcano to light a match," while her brother describes his situation more bluntly: "I need sex, I need a lot of sex."

The trick of the screenplay is that whereas we might not normally find much sympathy for a bunch of characters who are screwing each other over, Gwyn's familial relation to each person, coupled with her own innocence and likability, eases us into the position of viewing adulterers with understanding. Sarah Jessica Parker takes on this make-or-break role with complete assurance, and it's easily one of her best roles, allowing her to be comic, confused, intelligent and sexy all within the same film.

Frankel also makes swift use of explanatory flashbacks, visually pleasing Miami locations and several attractive supporting characters (including Naomi Campbell and Antonio Banderas as two very understandable subjects of temptation) to get his points across. This breezily played-out formula proves capable of sustaining the entire film, despite the fact that few of the individual plotlines go anywhere unexpected.

The only place where Frankel's Woody Allen inspiration fails him is in his unrestrained use of topical references to add spice to the dialogue. Allen paid the price with such tactics in the early '70s, making cracks about the likes of Howard Cosell that only date his movies today. Frankel falls into the same trap, forcing Parker's character to drop comments about postal workers, the ozone, Rush Limbaugh and so on. Sure she's an advertising copywriter, but these sorts of references seem forced, and within a few years will undoubtedly stand out like a sore body piercing (to use a topical reference).

One other complaint: While Miami Rhapsody's moral point--that relationships can work despite infidelity--has validity, Frankel cops out on showing the flip side. Without exception, all of his characters who engage in hanky panky find love and happiness by film's end, and those who are cuckolded end up taking back their unfaithful mates. Frankel may be trying to keep his story simple, but by avoiding at least one instance in which adultery yields permanent negative consequences, he comes dangerously close to becoming a panderer to rationalization. What's the point of breaking down one fairy tale if you only replace it with another?