You have to give M. Night Shyamalan credit for daring to be different. His seventh movie may mimic the creepy atmosphere his previous films have been famous for, but in narrative terms it’s certainly sui generis, a sort of weird modern fairy tale that fashions its own unique world even more than “Unbreakable” did and takes turns that the viewer certainly won’t be able to anticipate. In an era when cookie-cutter, by-the-numbers movies predominate, that’s very much a point in its favor.

Unfortunately, “Lady in the Water” proves decisively that unpredictability isn’t everything. In fact, it’s so muddled and disjointed that in terms of both plot and tone it’s a movie in total disarray. The writer-director says that the script began as a bedtime story he concocted night after night for his children, and it has the rambling, off-the-cuff, anything-goes character of such made-up-on-the-spot tales; in its completed form it has a beginning and end (and it mirrors Shyamalan’s usual concentration on lost, bruised, isolated people trying to find a purpose in life), but everything that happens in between has a one-damned-thing-after-another feel, with expository elements simply tossed in whimsically whenever a need is felt for some new wrinkle to push things forward. And the effort to give the narrative a deep meaning of universal scope (involving the future of humanity, no less) fails because it’s based on an absurdly flimsy idea (the notion that a book of philosophical doodlings would have the power, in this day and age, to “change the world”) which, to make things worse, is kept generalized and amorphous (we’re never given the slightest glimmering of what the contents consist of, apart from the apparent fact that they include the controversial contention that war is bad). And Shyamalan doesn’t help matters by playing the writer himself (not very well–he’s a pleasant enough presence but a hesitant, lightweight actor)–a tactic that implies that what he has to say in pictures like this one has Significance with a capital “S.” And that’s especially hard to accept in a dark fantasy that features creatures called narfs, scrunts and tartutic.

What’s “Lady” about? The central figure is Cleveland Heep (Paul Giamatti), his Dickensian surname mirroring a subdued, submissive personality. Heep is damaged goods–a fellow whose family was murdered, a tragedy that left him with a pronounced stutter and made him leave his job as a physician and become the put-upon super of a suburban Philadelphia apartment complex called The Cove. It’s in the swimming pool there that he discovers Story (Bryce Dallas Howard)–note what her name emphasizes as all-important. She’s a sort of mermaid without the tail, a Narf, resident of The Blue World, who’s been sent after centuries of disconnect between the two realms into the Human Side to inspire a chosen one with a message that will help end discord among men. Heep must not only aid her in finding The One among his residents, but assemble a crew–a guardian, a symbolist, a healer, and a guild–that will both help her fulfill her mission and protect her from evil wolf-like beings called scrunts that aim to prevent her return to The Blue World after it’s accomplished. (Also involved are the monkey-like tartutic, three beings that apparently maintain order between narfs and scrunts; but their appearance is so off-handed and abrupt that it’s hard to tell.) All this seems absurdly complicated, but happily there’s a Korean resident who knows all about the narfs and can enlighten Cleveland on the details.

Anyhow, much of the picture’s lurching, ludicrous plot involves Heep’s efforts to identify the people designated to play the various roles in Story’s story. Among those who eventually become involved are a crossword-puzzle addict (Jeffrey Wright) and his young son, the free-spirited daughter (Cindy Cheung) of that Korean woman, a would-be writer (Shyamalan) and his sister (Sarita Choudhury), a reclusive sage (Bill Irwin), an animal-rescue lady (Mary Kay Place), a body-builder (Freddy Rodriguez) who actually builds only half his body, a bunch of loquacious layabouts headed by a self-possessed Brit (Jared Harris), a family with five daughters, and an assortment of other peripheral figures. And there’s a new tenant–a pompous book-and-movie critic named Farber (Bob Balaban) to whom Heep turns for advice.

This jumble of weird characters remains throughout just that–a jumble. Only Cleveland, on whom Giamatti enthusiastically lays his entire repertoire of ticks, stutters, hesitations and whimsical schlubiness, emerges as anything remotely like a real person; everybody else remains an oddball type or symbol of something or other, and though the cast is composed of talented people, none are able to shine with the exception of Balaban, who revels in Farber’s smugly nasty attitude–even if the character’s habit of commenting on cinematic cliche (presumably as a way of italicizing how this picture avoids them) tends to stop things in their tracks–and Cheung, whose machine-gun delivery of broken-English at least has some verve, though it may well strike some as Charlie Channish. (The occasional shafts of humor, though, are like oases in the otherwise heavily self-important movie.) Even Howard, who’s second-billed, is given little to do but appear winsome and smile angelically. (She also periodically disrobes, but is always photographed discreetly in such states.)

But the small army of ill-defined characters isn’t the only problem; the narrative is a mess, too, beginning with a solemn animated segment outlining the basic premise (and which will probably cause some viewers to tune out immediately) but then constantly swerving and back-tracking to provide additional information as needed. The whole thing gets sillier and sillier as it goes along, and even if you’re willing to give it the benefit of the doubt for a while, eventually you’ll give up. The presentation is no help. Shyamalan and his team–cinematographer Christopher Doyle, production designer Martin Childs, art directors Christina Wilson and Stefan Dechant, set decorator Larry Dias, and the effects team headed by supervisor Edward Hirsch and creatures designer Crash McCreery–apparently aimed at a kind of magic realism, or more properly a mixture of ordinary scruffiness and mythic enchantment, but it doesn’t come off: the final product is just murky and visually dull, and the beasties in particular are amateurishly rendered in this day of cutting-edge CGI work. Even the prosthetics that Rodriguez wears look utterly fake. (The homeliness may be intentional, of course, but if it’s supposed to add to an old-fashioned mystical feel, it’s a plot that doesn’t work.) James Newton Howard’s score works overtime to create an ambiance of childish wonder and underlying menace, but it too comes across as second-rate. Maybe the late Jerry Goldsmith or Danny Elfman could have managed something more.

The fact that one of the main characters in “Lady” is a supercilious critic who bad-mouths formulaic movies but whose absolutist pronouncements turn out to be wildly wrong-headed (and lead to his own demise) may be intended by Shyamalan either simply to attack reviewers who have had bad things to say about his earlier movies (in which case, he’s nothing more than a peevish and juvenile joke), or to try to inoculate this one against their predictable assaults by saying to “regular” audiences, “See what these people are like?” But Farber is just one more miscalculation. For one thing, despite the fellow’s arrogance, the director would have to agree with him that most movies are made by rote–his entire career of trying to surprise us with his own pictures is evidence of that: the fact is that the critic might be an unpleasant guy, but he’s basically right. On the other hand, audiences who plunk down their hard-earned cash at the boxoffice are as likely as the critics to be puzzled and irritated by “Lady in the Water,” a movie that, curiously, is, in its own way, as smugly self-satisfied and sure of itself as Farber is. It’s a very shaggy-dog story that may earn points for individuality but surrenders them all back on grounds of poor construction, mediocre execution and sheer, almost gleeful absurdity. You won’t see anything else like it this summer, and you’ll really be glad about that.