Joel and Clementine meet on a wintry beach in Montauk, Long Island. They are not alike. She is outgoing, impulsive, and mercurial. He is bookish, shy, and probably a manic-depressive. They fall in love. In their own quirky ways they try to give what the other wants and needs. They fail; they hurt each other. If that were all that happened to these two souls, played by Jim Carrey and Kate Winslet, it would be hard to differentiate Eternal Sunshine from a thousand screen romances.

But in the hands of Charlie Kaufman, the screenwriter behind Being John Malkovich and Adaptation, what else happens to Joel and Clementine -- and, crucially, how we see it unfold -- is spun into a mind-blowing romantic-comedy. Kaufman and director Michel Gondry mold the notion of memory tampering into a funny, fetching, and funky cinematic experience.

So much can get in the way of two people staying together. Moviegoers have Kaufman and Gondry to thank for adding the rather tame science-fiction concept of erasing a person's memories to the list of obstacles. To top it off, they use it to bring the pair back together. Their collaboration on this suspenseful and emotional fantasy is without gloss or gimmickry. It's giddy perfection.

What happens, in a nutshell, is that Clementine breaks up with Joel and, desperate to move on, undergoes a procedure whereby all memories of him are wiped clean from her brain. Joel inadvertently finds out and decides to undergo the same procedure to forget all about Clementine. He asks the white-coated man in charge (Tom Wilkinson) if there will be any brain damage, to which he replies: "Technically speaking, the procedure is brain damage." Two technicians, played with nonchalant lunacy by Mark Ruffalo and Elijah Wood, come to Joel's apartment and start zapping away at his brain. Something goes awry and Joel proceeds to have the most entertaining out of body experience ever recorded on film.

Be sure to accompany him through the looking glass and watch his memories of Clementine disintegrate. Witnessing the relationship simultaneously get pieced back together is a bigger joy. Eternal Sunshine of the Spotless Mind is about two individuals given the opportunity to dissect their relationship -- to revisit, however foggily, the lost chances, botched moments and to rewrite their history. It convincingly documents how a relationship actually looks in one's memory, how it appears to the mind's eye. Moving romantic interludes are spliced together with the fights, the fears, the unbearable tension of being with someone as well as being apart from them.

After recent chronology-scrambling movies such as Memento and 21 Grams, the movie might sound annoying or a chore to follow. Yet the pattern of human intimacy is packaged in a way that doesn't feel like a showy exercise or clever puzzle. There's a nimble matter-of-factness to the premise and its execution. Kaufman and Gondry aren't toying with viewers; seeking to entertain, they've created something emotionally and cognitively arresting. Eternal Sunshine has formal integrity. Nothing is out of place or should be moved. The music, cobalt cinematography, and understated special effects are all of a piece.

The performers also exercise restraint. In Joel, Carrey may finally have found his Oscar-winning role. At first blush his performance doesn't dazzle, especially when compared to the narrative pyrotechnics surrounding it, or even Winslet's Clementine. But credit Carrey for making Joel a strong character whose romantic will binds the film together. Winslet has finally made amends for the watery Titanic. The supporting actors, including Kirsten Dunst in the vital role of the mind-eraser's office assistant, are also magnificent.

As crazy as it is, Eternal Sunshine is an extremely traditional and hopeful movie. If you find the ending incongruously schmaltzy, you weren't paying attention to these two screwed up people. Joel and Clementine's future is going to be rocky to say the least. Bring it on.

(Released by Focus Features and rated "R" for language, some drug use and sexual content.)