The Curious Case of Benjamin Button, inspired by F. Scott Fitzgerald’s farcical retort to the notion, espoused by Mark Twain, that the best things in life happen at the beginning and the worst at the end, demands a generous leap of the imagination. Fitzgerald dedicated roughly 25 pages to his whimsical tale of a man who begins life as a doddering senior and grows progressively younger. Here, director David Fincher and screenwriter Eric Roth attempt a bold re-imagining, using Fitzgerald’s premise as the foundation for a heartfelt rumination on the drawbacks of living life in reverse.

Born with cataracts, arthritic knees and enough wrinkles to suggest a man – albeit a very, very small one – well past the age of Medicare eligibility, Benjamin (Brad Pitt) is understandably baffled by his condition. Abandoned by his father after his mother dies during labor, he is raised in an old-age home where he seems to fit in quite nicely, save for his uncommon energy and a lingering desire to play with his food. All he lacks, it seems, is a proper childhood.

Sure, he can drink and carouse in brothels long before the other kids his age reach puberty, but there’s an unmistakable sadness in Benjamin Button, a desire to fit in sated only by his friendship with Daisy, a little girl who sees past the liver spots and thinning wisps of silver hair and is attracted by his youthful élan. It is their relationship, as Benjamin slowly recedes into boyhood while Daisy gracefully advances in age, that Fincher and Roth (Forrest Gump) make the focal point of a movie that begins at the end of the First World War and ends, somewhat ominously, as the first waves of an impending flood crash down on New Orleans.

What compelled Roth to relocate Benjamin Button, a Baltimorean in Fitzgerald’s story, to the Big Easy? Beats me. As he did in Gump, the veteran screenwriter sets his story against a backdrop of current events – among them, the Second World War, the Fab Four’s British invasion and, ultimately, Hurricane Katrina – presumably to mine them for pop hits and poignant memories.

His latest effort is far less cloying than Gump (though, by the very nature of its premise, just as gimmicky) and Fincher’s film is the better for it. It is a triumph of technique, from Claudio Miranda’s handsome cinematography to the brilliant makeup job that transforms Pitt into a sprightly codger, and it works for the better part of nearly three hours as an intensely touching romance. Yet its interior logic falters just before it arrives at its watery conclusion.

It’s a minor complaint, really. Though of marathon length, Benjamin Button’s journey is smartly paced and surprisingly grounded. His is a problematic learning curve – rushed into a kind of superficial maturity as a child, he gains the perspective that comes with age and experience just as he begins his regression to boyhood. He and Daisy meet somewhere in the middle, and their courtship is star-crossed from the start. Their hearts are willing and perfectly matched, making it all the more agonizing that their bodies are doomed to lose a race against time.

Although Pitt carries the film capably – he appears in nearly every scene, thanks to some particularly artful sleight of hand – it is Cate Blanchett, as the adult Daisy, who brings the passion to their abbreviated romance. When we first meet her, she is a fiery young woman worldly enough to intimidate an old-fashioned country boy like Benjamin. Her impulsiveness is tempered with age, of course, but her spirit remains unbroken throughout. She succeeds, after years of trying, in hungrily drawing her childhood playmate out of his reticent shell, but the reward is bittersweet: No sooner do they find the happiness they’ve spent their lives searching for than Benjamin withdraws again to play out the string of his strange mortal passage. Wounded but resigned, Daisy is left to grieve for them both.

If anything, Pitt’s is the less obviously rewarding of the two roles. Though some have criticized his approach as restrained to the point of detachment, his understated performance has its virtues. For all his extraordinary adventures, there is an underlying mournfulness in Benjamin brought on by the dawning realization that he can never grow old with the ones he loves. He is a freak, isolated from the rest of humanity by his unique genetic quirk, yet he feels increasingly the sadness of the human condition. Maybe Twain wasn’t wrong, after all.

There is much to appreciate in The Curious Case of Benjamin Button, which is as much a product of Fincher’s meticulous craftsmanship as his Fight Club or last year’s Zodiac. The film was clearly a delicate undertaking, and it is ambitious enough that a misstep or two can be forgiven. Born with the body of an infant and the facial features of a man well past his prime, does it not stand to reason, by the movie’s own logic, that Benjamin Button should end his life trapped in the body of an old man with the face of a baby? A grotesque thought, perhaps, but no more surreal than the story itself.