Starring Brad Pitt and Cate Blanchett. Rated PG.

The Curious Case of Benjamin Button's greatest trick is its ability to transcend all its gimmicks—both narrative and digital. The story centres on a character who ages backward, and director David Fincher uses computer-generated hocus-pocus to transform Brad Pitt from the beginning's shrivelled, cataract-ridden toddler to a preternaturally young buck straight out of A River Runs Through It. Rooted in our obsession with mortality, this oddball epic ends up being one of the most unusual, and unusually moving, films of the year.

If the central premise feels Forrest Gump–like, it's because it's by the same screenwriter, Eric Roth, who has loosely adapted an F. Scott Fitzgerald short story. But Button is darker. As an aged Daisy (Cate Blanchett) lies dying in a hospital bed, she asks her daughter (Julia Ormond) to read to her from an old diary. It recalls the strange adventures of Benjamin Button (Pitt), a boy who looks so hideously shrivelled at his 1918 birth that his father immediately abandons him at an old-age home—where he fits right in.

Trapped in an old man's body, he craves adventure, joining a tugboat crew and sailing right into World War II. Button waits for the day he might meet in the middle with Daisy, a ballet star he befriended when she was a child. But what happens after that, as he descends into childhood and she struggles with aging?

Packed with period detail, Button looks striking, especially in a sepia-toned New Orleans that's all ceiling fans and trees that weep Spanish moss, but the movie hinges on its performances. Pitt is subtle and sympathetic, and Tilda Swinton, as the adulteress he meets at a Murmansk dock stop, is as well-carved as an ice sculpture. Only Blanchett is disappointing here—a little too Blanche Dubois.

Fortunately, this wandering, two-and-a-half-hour odyssey is so rich in metaphorical touches—a clock that runs backward, a man struck by lightning-that she and Pitt's lack of chemistry doesn't matter much.

Like that lightning, fate follows us, but we should live life, as Benjamin Button does, as if we were given a second chance at it. We would all love to turn the clocks back. For now, though, only Fincher and his high-tech wizards hold that power.