There's a difference between storytelling and myth-making. M. Night Shyamalan can be very good at the former, but he's not so hot at the latter with his latest film.

A tale that originated as a bedtime story Shyamalan made up for his kids, Lady in the Water carries much of the dark, broody atmosphere that's a signature in the writer-director's films, including The Sixth Sense, Signs and The Village.

The premise - a mystical water nymph living under the swimming pool of a drab apartment complex - is intriguing, yet the mythology Shyamalan builds around his main characters is forced, pretentious and outright silly at times.

Strong performances from Paul Giamatti as the complex's melancholy manager, Bryce Dallas Howard as the nymph and a plucky supporting cast of amiable weirdoes makes the fantasy occasionally palatable - but just barely.

Shyamalan's make-believe world is just too fatuous and corny. Disney, which released Shyamalan's big hits, balked at the script, and the director stomped off to Warner Bros. to make Lady in the Water (a book timed to the movie's release, The Man Who Heard Voices: Or, How M. Night Shyamalan Risked His Career on a Fairy Tale, recounts Shyamalan's break with Disney).

It's hard enough for some hard-nosed moviegoers to accept the nasty orcs of Mordor in The Lord of the Rings or a talking lion in The Chronicles of Narnia, and those movies come with decades of literary veneration.

So it's a leap of faith many won't care to make when Shyamalan's characters start babbling about creatures called narfs, scrunts, the tartutic and the great eatlon.

Compounding viewers' unwillingness to suspend their disbelief is the disjointed, herky-jerky expediency with which the human characters decipher the mysteries surrounding the nymph's plight and settle on the strange course of action they must take to speed her back to her own domain. To add another groaner, her realm is called the Blue World.

Blue world would be a good name for the Cove apartment complex, where dispirited manager Cleveland Heep (Giamatti) wanders about fixing lights and toilets while quietly harbouring grief over a past tragedy.

Perpetually bathed in dusky twilight, the Cove is populated with oddballs and loners, many trying to bury themselves from the rest of the world.

One night, Cleveland discovers a nymph - or "narf" - named Story (Howard) has been living in a chamber beneath the swimming pool. Story's from a parallel world sent to help violent humanity reconnect with its spiritual, magical side, and Cleveland learns - through contrived and dubious means - the importance and tactics of sending her back home.

There are creatures bound to help her, others that aim to stop her, and denizens of the Cove have designated roles to play in Story's fate. Shyamalan piles it on like the arbitrary rules of a video game, to the point where a what-the-heck-is-going-on factor drowns the filmmaker's attempt to invoke childlike wonder.

The real wonder is that the actors are able to maintain straight faces amid the movie's preposterousness. It's almost worth seeing Lady in the Water just for the warmth and decency Giamatti injects beneath his character's bottomless anguish.

Howard, the sparkling star of Shyamalan's The Village, is a luminous presence, though she's never allowed to stray far from Story's hushed stoicism.

Generally taking bit parts in his films, Shyamalan here steps into a bigger role as a writer with an integral connection to Story. Given the nature of his character - a man with momentous things to say about humanity - you've got to wonder if Shyamalan's trying some mythmaking in his real life, with himself starring in his own fairy tale.

Highlighting the rest of the supporting ensemble are Sarita Choudhury as Shyamalan's sister, Bob Balaban as a standoffish new tenant, Jeffrey Wright as a crossword-puzzle fan, Freddy Rodriguez as a bodybuilder with an unusual goal, Cindy Cheung as a vivacious student, Bill Irwin as a shut-in and Jared Harris as a middle-aged slacker.

There are chills and scary moments, though nowhere near as many as Shyamalan's past hits have offered. Lady in the Water is more about mood than menace.

It would be nice to say Lady in the Water is a story for the kid in all of us. But it should have remained a story just for Shyamalan's kids.

Two stars out of four.