Like anyone who's a certified, if not certifiable, Tim Burton fan, I'm always desperate to see him play out his fantasies on a scale of oddball grandeur. It's just not enough, somehow, for him to make a conventional thriller with outré Burton ''touches,'' like ''Sleepy Hollow.'' I want him to get lyrically punch-drunk, moonstruck, cracked: in touch with his inner demon child. I want to see his imagination splattered all over the screen.
There are long stretches of Burton's Big Fish in which you can feel the loopiness of his spirit busting free. Based on a novel by Daniel Wallace, the movie is a gently overstuffed cinematic piñata, crammed with tall tales -- with giants and circuses and fairy-tale woods, plus a huge squirmy catfish, all served up with a literal matter-of-fact fancy that is very pleasing. ''Big Fish,'' however, is also a father-son reconciliation movie that wants to give you a big cry. I'm generally a sucker for that sort of thing, but the movie ends up milking the audience when it should soar.
For much of ''Big Fish,'' we're inside a crackpot magical-realist version of the American South, watching the storybook memories and fantastical whoppers -- or are they true? -- of a man named Edward Bloom. We see him, at first, as an old, dying patriarch, played by Albert Finney with bullfrog jowls and a drawl he chews on like the sweet crushed leaves of a mint julep. Finney, evoking the operatic splendor of Charles Laughton, makes Bloom a blustery, arrogant crank, at loggerheads with his glumly rational son, Will (Billy Crudup), who resents his father because he has never known anything about him except for the outlandish yarns he tells. But then the movie swan-dives right into those stories, and suddenly Bloom is no longer a smug, cantankerous big daddy. He's a lean and happy young man, played by the spectacularly ingratiating Ewan McGregor, agleam with valor and optimism. ''Big Fish'' turns into a wide-eyed Southern gothic picaresque in which each lunatic twist of a development is more enchanting than the last. It's like ''Forrest Gump'' without the bogus theme-park politics.
As a boy, Edward looked into a witch's eye and foresaw his death, and it's that macabre knowledge that grants him freedom in life: He doesn't have to worry about how he's going to go. In the idyllic '50s small town of Ashton, Ala., he's the hero of the science fair, but it's only when he saves the town from the carnivorous threat of a local giant that it's clear he and the film are destined for grander things. The giant is one of Burton's purest creations: a doleful, 10-foot-tall outcast who looks like a fun-house Vincent Gallo and walks with a shuffle as crooked as his oddly angled physique.
It's a sign of Edward's generosity that he befriends this tender misfit, and he soon lands in the town of Spectre, a woodland heaven on earth that's far too happy and square for its own good. Burton decorates this vaguely cultish hoedown paradise with spooky details, like the banjo kid from ''Deliverance'' all grown up and Steve Buscemi flashing his gums. Edward, on the other hand, is too ambitious to stick around, and so he joins the circus, led by Danny DeVito as a master of ceremonies who's beastlier than he looks. Our hero then spends a year trying to locate Sandra (Alison Lohman), the pristine beauty he glimpsed in the stands for a moment that literally stopped time.
McGregor may be the only young actor today who can summon the idealized ardor of a vintage Hollywood leading man. His ebullient, gap-toothed gaze is just off-center enough to make his handsomeness look like it belongs to reality. Here, as in ''Moulin Rouge,'' you fall in love with Ewan McGregor falling in love. Once he's finally tracked down Sandra, she looks out the window of her sorority to see him standing, miraculously, in a field of daffodils, and it's an image of devotion perfect enough to make you laugh.
It also makes you wonder: How did Edward the fearless, soft-shoe romantic ever turn into Finney's crusty narcissist? That's a question the film raises but never answers -- even if the tales are Edward's fantasies, and even if Sandra herself ends up aging into the radiant Jessica Lange. Transporting as much of it is, ''Big Fish'' is so eager to bamboozle you, over and over again, with its message about the glories of storytelling that it never fully connects those stories to the conventional, generic reconciliation at its core. The movie is a box of chocolates that turns into a box of Kleenex: By the end, you know all too precisely what you're going to get.