This is the very model of the modern musical comedy—there’s absolutely nothing original in it. The songs aren’t new, of course—they’re a collection of old tunes by the group ABBA, shoehorned into a narrative cobbled together, first for the stage and now for the screen, by Catherine Johnson. To at least one set of ears the music sounds blandly uninspired and the lyrics even more pedestrian and repetitive, so that the net effect is like being trapped in a stalled elevator for a couple of hours with the Muzak still blaring. Those for whom the songs are old friends may feel differently, though.

But Johnson’s script isn’t really original, either. The threadbare plot, in which a girl invites to her wedding three old friends of her mother, any one of whom might be her father, hoping to identify the dad she’s never known, is derived—without acknowledgement—from a 1968 movie, “Buona Sera, Mrs. Campbell,” which was set in Italy but had much the same scenario. Campbell switches the story to an Aegean island, but otherwise it’s pretty much the same.

In this version, the bride-to-be is Sophie (Amanda Seyfried), who’s engaged to a handsome guy named Sky (Dominic Cooper). She says that until she meets her dad a part of her is missing, and from the way she acts, she’s right about that. (It’s called a brain.) Her mother Donna (Meryl Streep) runs a little hotel, and has raised her as a single mother, never revealing who the father was. So Sophie invites the three most likely candidates, whose names she found in an old diary—Sam (Pierce Brosnan), a divorced architect; Harry (Colin Firth), an unwed, super-rich banker; and adventurer Bill (Stellan Skarsgard)—to the ceremony, much to her mother’s chagrin.

Donna copes at first by continuing to attend to the wedding details with her high-spirited pals old Rosie (Julie Walters) and Tanya (Christine Baranski): the horseplay among them is so overdone it makes “Sex and the City” seem tame by comparison. But ultimately she finds her interest in Sam rekindled as the plot proceeds to its foreordained conclusion with nuptials, the revelation—or not—of paternity, and all sweetness and light.

The movie wants to be a high-spirited romp—just naughty enough to tickle older viewers (especially women), but not enough to offend them. But it fails, not just because the script is so slight and the songs so much fluff but because, though the setting is lovely, it looks awful. That’s because director Phyllida Lloyd apparently has no idea where to place the camera or frame a scene, and cinematographer Haris Zambarloukos doesn’t seem to have offered any assistance to her. And the messiness is compounded by the erratic editing of Lesley Walker. The dance sequences, with choreography credited to Anthony Van Laast, are particularly poor, given over either to clumsily-done attempts to mimic Busby Berkeley or sloppily constructed montages. And, of course, the whole thing is almost incredibly garish.

And the casting! Meryl Streep? That might cause you to wonder; but watching her may change your wonder to jaw-dropping astonishment. Actually she can sing, but her performance has an air of desperation about it, all frenzied and overdrawn—you could probably get the same effect if, to take the opposite extreme, Adam Sandler tried to play Hamlet. Brosnan, Firth and Skarsgard are equally at sea, as it were (and more so where the vocalism is concerned.). The young couple—Seyfried and Cooper—are better suited to such stuff (though they’re given some of the weakest tunes), but by far the most comfortable are Walters and Baranski—especially the latter, who belts out one beach number with the skill of the Broadway pro she is (unhappily, the song is awful and the choreography worse). Everything reaches its nadir in the numbers that accompany (and follow) the final credits, which descend to a level of embarrassment it’s hard to comprehend.

An interesting sidenote, incidentally, is that there was a true musical version of “Buona Sera, Mrs. Campbell.” Produced on Broadway in 1979, it was called “Carmelina,” and came from two respected veterans—Alan Jay Lerner and Burton Lane. It was a failure, lasting only seventeen performances. That’s usually blamed on weaknesses in the libretto and inept staging, but certainly not on the score, which—as a cast album still floating around shows—was very fine (much better, in fact, than the one here). But of course “Mamma mia!”—which has been a huge success—isn’t a real musical. It’s the sort of splashy exercise in mindless nostalgia that passes for entertainment nowadays. With its inane songs and mindless exuberance, the picture is like one of those brightly colored tropical drinks that’s been sitting on a bar all night. It might look tasty, but drinking it can only elicit one response: Yuck! That applies here, too.