An ensemble filled to the brim with talented A-list Hollywood actors in a multi-story ode to the title holiday sounds, by conception, like a can't-miss prospect. Nobody, however—not director Garry Marshall (2007's "Georgia Rule"), not the impressive cast, and certainly not screenwriter Katherine Fugate (2004's "The Prince & Me")—apparently paid any attention to what was on the page before production got underway. Neither, for that matter, were the performers tested to see if they shared chemistry with each other. Woefully mechanical and uninspired, "Valentine's Day" holds not a single genuinely romantic moment in its whole two-hour running time. How Marshall could so prominently miss the mark is anyone's guess, but, for a picture that is all about love and relationships, its lack of true feeling is a fatal error that makes its other hundred or so problems seem minimal by comparison.

Set from the early-morning to late-night hours of February 14, the Los Angeles-based story revolves—at least partially—around Siena Bouquet, a flower shop owned by nice-guy florist Reed Bennett (Ashton Kutcher). Having just proposed to sweetheart Morley (Jessica Alba), who instantly begins hiding her cold feet, Reed is on cloud nine until he takes the double order of cardiologist Harrison Copeland (Patrick Dempsey). Harrison wants one flower arrangement sent to his wife, and the other sent to his in-the-dark girlfriend, schoolteacher Julia Fitzpatrick (Jennifer Garner). Julia, as it turns out, is Reed's best friend, and now he has the tough job of breaking the bad news to her. Also stopping into the shop is elementary school youngster Edison (Bryce Robinson), experiencing his first pangs of love much to the chagrin of grandparents and guardians Estelle (Shirley MacLaine) and Edgar (Hector Elizondo), who have their own trouble in paradise when a long-kept secret is confessed.

Edison's after-school nanny is high schooler Grace (Emma Roberts), set to have sex for the first time with boyfriend Alex (Carter Jenkins) to commemorate the holiday. They are friends with teenybopper classmates Willy (Taylor Lautner) and Felicia (Taylor Swift), the interview subjects of a visiting reporter doing a story on young sweethearts. Alex, meanwhile, works at an Indian restaurant that annually hosts overworked, love-starved publicist Kara's (Jessica Biel) "I Hate Valentine's Day" dinner. Stressed out that no one else will show up, Kara busies herself with work during the day, teaming with sports journalist Kelvin Moore (Jamie Foxx) and PR head Paula Thomas (Queen Latifah) to handle football player Sean Jackson's (Eric Dane) impending "will-he-or-won't-he-retire" press conference. Toss in Paula's new assistant, Liz (Anne Hathaway), who is hiding her moonlighting gig as an adult phone entertainer from boyfriend Jason (Topher Grace), and an airplane friendship that arises between passengers Holden (Bradley Cooper) and Kate (Julia Roberts), the latter on short military leave, and it's a wonder the movie doesn't run three hours rather than two.

The only even marginal innovation in "Valentine's Day" is waiting to see how the intertwining subplots and characters mingle with one another, but this narrative style has been done many times before and almost always better than it is here. From Robert Altman's groundbreaking oeuvre to 2003's cheerful "Love Actually" to 2009's wiser, altogether stronger "He's Just Not That Into You," tossing big ensembles together to represent some particular microcosm within the world has become a subgenre in and of itself. Here, director Marshall and scribe Fugate are so pleased with their cast that they totally forget to create memorable or even all that diverse of people for them to play. The lot of them go through the rusty, discouragingly by-the-numbers motions with little substance or clear arcs to cling to. As for whose arms each of them find their way into by the end, the script is so vacant of originality and so dependent on overused clichés and conventions that all but one pair, non-romantic in nature, is anything but an instant foregone conclusion. The rest of the couplings, like the film itself, are about as artificial and see-through as they come.

Schmaltzy and stale, "Valentine's Day" travels down a long, straight line, tediously low on authentic emotional or comedic elements. There's simply no ambition involved in director Garry Marshall's work here—no drama that effectively pulls at the viewers' heartstrings, no humor that is worth more than a passing chuckle, no music cues that indelibly compliment the onscreen goings-on, and no relationships that go beyond obvious, telegraphed or two-dimensional. Certain characters have more screen time than others, while some are so misused that they literally go nowhere (Morley, Willy and Felicia, for example). The precious few minority characters, from Reed's Latino coworker Alphonso (George Lopez) to African-Americans Kelvin and Paula, are either handed extras as love interests or are all but stripped of their own sexual orientation in order to make room for the conflicts of all the whiteys in the cast. Even more offensive than that is Marshall's inappropriate, strained, and faux-sincere attempts at political correctness, tossing in a little people couple in one shot who wordlessly walk out of the flower shop together, never to be seen again, and a severely handicapped child in a scene set at an airport that is downright skin-crawling in its blatant exploitation. As for the film's one same-sex liaison, it is used as a third-act plot twist rather than treated as an organic relationship running throughout the narrative. For this, Marshall demonstrates his own lack of acceptance of homosexuality, forcing it to serve as a punchline rather than a venerable storyline worthy of attention. Indeed, he might as well have topped things off with a lisp and a lot of animated hand-waving.

The actors are all attractive and in a lot of cases charming enough to nearly distract the viewer from the film's shallow waters. Still, very few of them get a chance to truly stand out. The centerpiece bond between lifelong pals (and maybe more) Reed and Julia should be where the movie's heart lies, but an otherwise affable Ashton Kutcher (2008's "What Happens in Vegas") and Jennifer Garner (2009's "The Invention of Lying") simply don't get the material or exhibit the spark of best friends meant for each other. Jessica Biel (2007's "I Now Pronounce You Chuck and Larry") has some fun as the self-proclaimed neurotic Kara, but the script doesn't do enough with her to make her turnaround on love at the end believable. Delivering the most rounded character—one who doesn't just get lost in the sea of pretty faces—is Anne Hathaway (2008's "Rachel Getting Married"). As Liz, a college graduate struggling to make something of herself while forced into being a phone sex operator to pay her college loans and make ends meet, Hathaway displays potent comic timing, pathos, and something verging upon real depth. On the other end of the spectrum, Taylor Lautner (2009's "New Moon") and especially musician Taylor Swift, making her feature acting debut, are mediocre bordering on awful as Willy and Felicia. Neither seems at all at ease in front of the camera, though Lautner does get an unintentional laugh when he remarks that he's uncomfortable taking his shirt off in public. The irony of this line was probably lost on all involved during filming.

"Valentine's Day" is an extraordinarily unextraordinary wasted opportunity, a motion picture that could have, with the right handling, become the cinematic be-all-end-all for hopeless romantics everywhere. Instead, it's a bland and unenlightening product-by-committee that never rises above a turgid crawl and hasn't an ounce of spontaneity or sweetness in it. For lovebirds searching for a film to see in theaters this Valentine's Day, they are apt to feel warmer, gushier feelings by checking out the stuck-on-a-ski-lift thriller "Frozen." That's not hyperbole.