In Face/Off, we know who the antagonists are; we know why they hate each other's guts; and we know why they can't just let their antagonism drop. The marvel is that we find all this out before the opening credits have even finished. Even though it's as farfetched as the genre currently demands, Face/Off is nevertheless a beautiful, exhilarating, and surprisingly touching piece of moviemaking--the work of a director who understands that cinematic excitement must be meticulously prepared and constructed, not just conjured in a cloud of zap and zowie.

Face/Off is the first action movie since the original Die Hard that demands first-rate actors in every major role--and uses them as something more than window dressing. John Travolta plays Sean Archer, a crack antiterrorist agent who has devoted six years of his life to chasing one man: Castor Troy, the flamboyant, diabolical archvillain who cost Archer the life of his son. Travolta broods intensely; Nicolas Cage, strutting like a dirty wrestler, does Troy as a lip-smacking psycho hedonist with a yen for babes and Chiclets.

Through a series of convolutions too crazy to list--but directed briskly enough to overcome their patent lunacy--Archer agrees to assume, through surgery, the face of his captured nemesis so that he can learn the whereabouts of a ticking megaton bomb hidden somewhere in Los Angeles. Literally imprisoned in the identity of his loathsome enemy, Archer is horrified to receive a visitor: Castor Troy, newly outfitted with Archer's face, his identity as a cop--and his unsuspecting wife and teenage daughter.

The astounding stunts and shoot-outs may merit top billing, but the movie wisely focuses on its characters. As much setup as it takes, the way-out premise, cooked up by screenwriters Mike Werb and Michael Colleary, becomes pretty much an acting exercise--a fascinating one. For the rest of the movie, Cage must play the morose Travolta of the movie's first half, and Travolta must step into the role of Cage's wacko hipster. Having two actors this gifted suddenly slip on one another's mannerisms turns the movie's role-playing gimmick into a truly resonant joke.

Of the two, Travolta gets the flashier part. In Archer's body, Troy masquerades as a cartoon hero and a Lifetime Channel dreamboat, and the criminal and the actor playing him swagger through the movie on a high of lewd amusement. But Cage as Archer gives the movie its emotional force. Every time his Archer looks in the mirror, he sees the face of the man who killed his son, and Cage charges through the movie with a father's grief, a husband's rage--and considerable existential confusion. How do you live with becoming everything you hate?

This question lies at the heart of the operatic Hong Kong thrillers that built director John Woo's reputation. To a mass audience, Woo is known less for his own movies than for the facile tricks Hollywood swiped from them--the slow-motion leaps, the heroic gunplay that slaps a blazing weapon in both hands. (These, oddly enough, are the least inspired elements of Face/Off, although they're still pretty sharp.) But in his best films--The Killer, Hard-Boiled, the devastating Vietnam War drama Bullet in the Head--Woo obsesses over the idea of doubles who act out our darkest impulses. In Face/Off, even Archer's troubled wife, portrayed wonderfully by Joan Allen, has an opposite: Troy's tough moll, played with maternal ferocity by the super-cool Gina Gershon.

The line that separates cop from criminal (and good from evil) is hair-trigger thin, and Woo's heroes struggle to remember where they stand. This isn't just tough-guy posing, despite all the gun-waving and toothpick-chewing. In Woo's movies, God is in heaven, not on earth, and in His absence, loyalty and rigid adherence to codes of honor are akin to divinity. Every conflict therefore assumes both an internal and external dimension. Woo's florid religious symbolism makes clear that his heroes are waging a battle for salvation over their fallen selves--a victory over the evil twin in the mirror.

That makes Woo the ideal filmmaker for this story, and he responds with a masterful job of direction. Every shot is visually striking; the many knotted plot threads remain easy to follow; the use of slow-motion and dissolves is as bold as editor Christian Wagner's cross-cutting. And the action scenes! Nobody kicks ass like John Woo at full throttle, and Face/Off includes about a half-dozen action sequences that are at once rhapsodic, thematically expressive, and white-knuckle tense. My favorite (of many) climaxes with Travolta/Cage and Cage/Travolta on opposite sides of a mirror, each staring at the image of the man he hates most--his own reflection.

What's doubly amazing is how clearly Woo envisions the jazziest mayhem. We always know how big a room is, where the principals are in relation to one another, what the forces of conflict are. During the movie's grandiose finish, when a dozen combatants train guns on one another, Woo neatly establishes every gunman's motivation and his position in the room in seconds. He understands that the geometry of a gun battle involves more than lines of fire; it involves crisscrossed loyalties and intersecting motives as well.

Like his heroes, Sam Peckinpah and Sergio Leone, Woo expresses social and spiritual conflict through the American cinema's method of choice: balls-out orgiastic bloodshed. If Face/Off has a flaw, apart from its sheer implausibility--Archer's wife isn't going to notice the change in her husband's hands (and God knows what else)?--it's that the incidental violence is way too strong. Woo admirably doesn't sugarcoat onscreen deaths, but you still wince every time some poor bystander gets 187'd like Clyde Barrow.

Perhaps that's why many of the most memorable moments in Face/Off are the quietest--the meeting between Archer and a 6-year-old boy, or the heartbreaking scene in which Archer must meet his wife wearing the face of her son's killer. In its phenomenal action scenes and clever plotting, Face/Off restores vitality and virtuosity to a genre that has lapsed into lame repetition. But it accomplishes something only a handful of blockbusters have managed in the past decade: getting us to give a damn about the action onscreen.