January 4, 1996 | Once again, Terry Gilliam has seen the future, and it's a mess. In Brazil, his exuberantly paranoid vision of a post-1984 totalitarian state, he offered us a spectacularly seedy world filled with retrograde decor, malfunctioning artifacts and condescendingly sinister bureaucrats. But the day after tomorrow looks even less inviting in 12 Monkeys, Gilliam's latest effort. Little wonder, then, that the filmmaker is so eager to repeatedly leave tomorrow behind, to journey back to yesterday. Or today.

Constantly surprising and consistently unsettling, 12 Monkeys is an apocalyptic time-tripping fantasy that only gradually reveals its true intentions to the audience. James Cole, the frightened but fiercely resourceful protagonist played by Bruce Willis, often seems just as confused as we are. Indeed, when James is told by a 1990s psychiatrist (Madeleine Stowe) that he isn't really a time traveler at all, that he's suffering from a bizarre form of schizophrenic delusion, it's not so easy for the audience to dismiss her diagnosis. One of the many provocative aspects of 12 Monkeys is Gilliam's willingness, over long periods of the film, to allow for the possibility that everything we see and hear is the stuff of madness.

But there is method to this madness. Written by David Peoples (Unforgiven, Blade Runner) and Janet Peoples, his wife, and loosely based on Chris Marker's 1962 short film La Jette, 12 Monkeys begins in 2035, nearly four decades after a devastating plague has wiped out 99 percent of human life on earth. While wild animals roam through the crumbling remains of abandoned cities, survivors live in underground settlements where, for reasons never fully explained, the disease has yet to spread. The scientists who appear to run the settlements need a volunteer to travel back in time to locate the original source of the deadly virus. Since no one in his right mind would willingly accept such a mission, they draft James, a convict whose antisocial tendencies have not dulled his keen powers of observation.

Trouble is, nothing in the future works quite the way it should. The time machine ships James back to 1990, a few years too early for his dire stories of impending apocalypse to seem like anything but the ravings of a madman. So he's held in a mental hospital, where he arouses the intense interest of Dr. Kathryn Railly (Stowe), a psychiatrist with a special interest in doomsday fantasies. Cleverly, the movie implies that, because of her encounter with James, Dr. Railly's interest becomes an obsession, to the point where she's writing and lecturing on various forms of the "Cassandra complex," a condition she describes as "the agony of knowledge combined with the impotence to do anything about it." After one particularly well-received lecture, Dr. Railly is reunited with James -- six years after his inexplicable disappearance from a locked room at the mental hospital.

Dr. Railly is understandably terrified by her former patient, especially when he kidnaps her and forces her to drive him from Baltimore to Philadelphia. And her fears are intensified when she learns that James is on the trail of another person he met back in the mental hospital: Jeffrey Goines, a disturbed young man whose animal-rights activism has placed him in conflict with his scientist father (Christopher Plummer). Slowly, chillingly, it becomes clear that Dr. Railly isn't the only one whose life has been changed and shaped by James' inadvertent influence. Worse, it becomes equally clear that Jeffrey has both the means and the opportunity to turn James' worst nightmares into lethal reality.

Brad Pitt plays Jeffrey, and he is excellent. His star power undimmed by a bad haircut and jittery mannerisms, he manages to infuse his character with a weirdly charismatic charm, even when Jeffrey sounds most like an ecological terrorist. Better still, Pitt's attention-grabbing talent for mesmerizing through wild-eyed ranting is used here to nicely ambiguous effect. Just as Gilliam generates suspense by hinting that James may not be entirely sane, the filmmaker keeps the audience off-balance by suggesting that Jeffrey, too, should not be taken at face value. The elaborately complicated plot of 12 Monkeys is ingeniously wrapped up with an interlocking chain of ironic twists. Without spoiling any of the movie's surprises, it can be said that Pitt does much to make those twists dramatically sound and emotionally satisfying.

But Willis is the one who carries us through 12 Monkeys, serving as our surrogate as he and we try to make sense of a situation where the conventional parameters of time and space can expand or even completely disappear without warning. Willis has always been the most vulnerable of our action movie stars -- a large part of what made the first Die Hard so appealing was the possibility that, unlike Stallone or Schwarzenegger, Willis might actually fail to save the day. In 12 Monkeys, he eschews his winking irony and other superstar tricks to give a performance of impressive physicality and deeply felt desperation.

Willis has a tricky balancing act to pull off here. He must be appealing enough for the movie to remain plausible when Dr. Railly begins to trust James. (Stowe is very good at making the psychiatrist come across as much more substantial than the role is written.) But Willis also must appear impulsively violent enough to remind us why James is behind bars in the first place when we meet him in 2035. Much to his credit, and very much to the good of the movie, Willis is thoroughly convincing on both counts. And when James wonders aloud whether he's truly and completely bonkers, Willis wins your heart while he races your pulse.

Gilliam and his screenwriters play their cards very close to the vest -- occasionally withholding valuable information, often indulging in deliberately disorienting transitions. At times, you may feel like you're working just as hard as James is to keep track of what, when and how things are happening. In its seemingly freeform but rigorously disciplined structure, 12 Monkeys recalls another eccentric time-travel drama: Alain Resnais' Je T'Aime, Je T'Aime, a haunting stream-of-consciousness story about a man who is revived after an attempted suicide, then allowed to relive key events from his life in a time-travel experiment. (Unfortunately, the experiment is too successful -- the man gets to relive every key event, including his suicide.) And while 12 Monkeys is a great deal more accessible as an involving story, it is no less ambitious in its attempt to break free of conventional narrative form.

But not so free, it should be noted, that the movie falls into the lapses of logic that are common to time-travel movies. Unlike, say, the Terminator movies, which are based on the dubious premise that the future can be saved by altering the past, 12 Monkeys is too grimly rational to bother with hope. Very early in the story, it is firmly established that the scientists who send James back to our present are not trying to change things that cannot be changed. Rather, they transport James to the 1990s (and, during one brief interlude, to World War I) only so they can gain enough knowledge to devise a cure in their own time. Some may read into the final images of 12 Monkeys a tiny hint of optimism. Others will take the ending as Gilliam's way of showing how humanity will continue to make the same awful mistakes over and over and over again. Either way you care to look at it, 12 Monkeys is not a pretty picture. But its story of humanity stubbornly racing toward a brick wall of disaster has an undeniably powerful resonance, particularly at this point so close to the year 2000. Never mind Strange Days -- 12 Monkeys is the real masterwork of millenarian dread.