"You kill your film several times, especially by talking about it," says Italian auteur Guido Contini (Daniel Day-Lewis) at the beginning of "Nine." He is seated for an interview, speaking of his body of work and building buzz on his latest endeavor, a film about to go into production called "Italia." The year is 1965, long before DVD special features and director's commentary tracks, but Contini's words still apply. It might be fun for viewers to hear the intentions of a filmmaker, but doesn't that also, in a way, take away from the mysticism and interpretive qualities of the art form? What Contino does not tell his interviewer—or a later press conference—is that he also cannot talk about his upcoming picture, due to begin shooting in ten days, because he has no idea himself what it is about. A leading lady, actress muse Claudia (Nicole Kidman), is in place, sets are being built and costumes designed, but there's no script. Contini's journey toward creative cinematic rejuvenation as he also juggles the various women in his life—among them, long-suffering wife Luisa (Marion Cotillard); needy mistress Carla (Penélope Cruz); vivacious American journalist Stephanie (Kate Hudson), and a deceased mother (Sophia Loren) who haunts him—is the narrative's most prominent thread, one that may leave the average Joe moviegoer feeling disconnected as they scratch their head.

If the story is particularly concentrated and "inside" for big-budget mainstream fare, "Nine" is softened and made more palatable through its glorious threading of song and dance. Directed by Rob Marshall (2002's "Chicago") and adapted from the 1982 Broadway musical by screenwriters Michael Tolkin (2002's "Changing Lanes") and the late Anthony Minghella (2006's "Breaking and Entering"), the film is easily at its best when the beat gets going and the actors pour their emotions (and distinguished vocal chops) into their performances. Each number—portrayed as either a figment of Contini's imaginings or the internal thoughts of one of the females sprung to life—is interwoven into the plot, placed fairly evenly throughout, and are, by far, the reason to see "Nine." What is less satisfying are the melodramatic trappings of a protagonist who isn't exactly likable and whose choices—including repeated infidelity—are far from savory.

Because Contini's romantic foibles and ultimate resurgence as a visionary director are familiar and/or plodding, one catches him or herself growing a tad impatient for the next show-stopper to arrive. With the exception of "Unusual Way," performed by an untested and underused Nicole Kidman (2008's "Australia"), the musical set-pieces are worth the slow spaces in between. Marion Cotillard (2009's "Public Enemies") is pure magic as Luisa, her first of two songs, "My Husband Makes Movies," a shattering dramatic tour de force. When she arrives at the end of the number, her glistening tears lit not only by Contini's films, but with the knowledge that she will never come first (or second) in his life, it's as powerful as "Nine" gets. Penélope Cruz (2008's "Vicky Cristina Barcelona") is seemingly effortless in her charisma as Carla, a woman so in love with Contini (or, so in love with the idea of him) that she can't help but forget that both of them are married to other people. Cruz's "A Call from the Vatican" is sexy, flirtatious, fun and exhibits the actress' go-getter physical prowess.

As the no-strings-attached Stephanie, a journalist interested in more than just writing an article on Guido Contini, Kate Hudson (2009's "Bride Wars") is a good as she's been in years. A part written expressly for the screen (Stephanie was not in the stage production), Hudson ensures that she is a vital part of the ensemble, no more so than during the most purely catchy and entertaining song in the film, "Cinema Italiano." Stacy Ferguson (Fergie of The Black Eyed Peas) also genuinely surprises with the imprint she makes in the small yet intense role as Seraghina, a prostitute from Contini's childhood. And then there's Daniel Day-Lewis (2007's "There Will Be Blood"), never one to give anything but his all. He enlivens Guido Contini with a spectrum of layers and nervous quirks, a filmmaker whose ambitions as an artist are nearly unreachable and whose inability to stay truthful to his most valued relationships may one day leave him a lonely old man. Day-Lewis becomes Contini to the point where no other actor can be imagined in the role.

When "Nine" is fulfilling its duties as a musical, it's terrific. Despite using the same stylistic elements as "Chicago," director Rob Marshall is a talent who knows how to stage a big number and make it pop with excitement. The songs, however, are in service of a lesser script and story. Without them, the picture would crumble under heavy pretenses, slight characterizations, and fairly mundane conflicts that all boil down to one man's selfishness and disloyalty. Fortunately, "Nine" keeps things moving as the actors turn to belting. As the genre goes, this is a minor musical, but worth seeing all the same.