"The Road Warrior" begins with an excessively portentous prologue and ends with a perversely unsatisfying epilogue, but the movie that unfolds between these faulty borders is an adventure spectacle of extraordinary pictorial sweep and kinetic excitement.

The brilliant young Australian director George Miller actually possesses the flair for the exotic and epic depiction that John Milius kept groping for in the oafish "Conan the Barbarian." The action freaks who hoped to be transported into a realm of barbaric conflict and scenic grandeur by "Conan" will find the quality of illusion they were seeking in "The Road Warrior," which opens today at area theaters.

Moreover, the illusion is more imposing and haunting for being identified not with a remote barbaric past but with a sinister barbaric future. A flamboyant sequel to Miller's sensational debut feature, the baroque, teeth-gnashing chase thriller "Mad Max," which envisioned a post-industrial civilization on the brink of lawlessness and savagery, "The Road Warrior" leaps beyond the brink. The Dark Age foreshadowed in "Mad Max" is a vividly brutish, terrifying reality in the dog-eat-dog badlands of "The Road Warrior."

Mel Gibson's Max belonged to an elite corps of highway patrolmen who represented a last, supercharged line of defense against an encroaching social breakdown, symbolized by the crazed, suicidal degenerates challenging them for supremacy on the long, undulating highways of the countryside. Miller set the lawmen and the outlaws on a literal collision course, and while Max, peerless at the wheel of his black, streamlined V-8 Interceptor, survived all fero ious comers, he was left emotionally devastated by the loss of a wife and child caught in the cross fire.

Miller and his screenwriting collaborators, Terry Hayes and Brian Hannant, imagine in "Road Warrior" that several years have elapsed and that the impending breakdown has been hastened by a calamitous war. The survivors scavenge for food and dwindling sources of gasoline. Max, a scarred, graying lone wolf, is still in possession of the Interceptor, but it's battered and running low on fuel. Max tolerates one companion -- a stray dog in a red bandana -- but there's no love lost between "master" and "pet." Max expects the mutt to fend for himself; he won't even share a recovered can of dogfood.

Despite appearances, "The Road Warrior" was evidently not a premeditated sequel. While developing other script ideas, Miller and his associates began to speculate about the international success of "Mad Max" and concluded that they'd stumbled upon a premise that seemed to share common emotional ground with genres like the western and the samurai epic, although they'd thought of it as more of a horror vehicle. Eventually, Miller described "Mad Max" as a western: "It has the same story, but instead of riding horses the characters are riding motorcycles and cars. People say the western's dead, but it's not; it's become the car-action film."

Given this self-assessment, it's not surprising that the western influence is easily recognizable in "The Road Warrior," where Max discovers the equivalent of a beseiged fort -- a desert oil refinery -- and offers his services to its tenacious band of defenders, a civilized remnant surrounded by a bloodthirsty horde, ruled by a masked, despotic muscleman called The Humungus (Kjell Nilsson, a former Olympic weightlifter), heralded by a flunky at one playful moment as "The Ayatollah of Rock 'n' Rollah!" At first Max's offer is strictly mercenary, an exchange of raw skill and cunning for a precious tank of gas. As the story evolves and begins to acquire unexpected thematic depth, Max's role in the community's defense is obliged to become more cooperative and selfless. The obvious, inspirational expectation is that his ultimate contribution to this last outpost of humanity will prove an act of redemption.

Miller transcends his opening oratorical obstacle, but at the fadeout he leaves another stumbling block in the path of unequivocal heroic gratification. The story appears to be admirably contrived for a rousing finish, but Miller rejects the emotional logic of his own calculations, which imply that Max will cease to be a loner. Indeed, there are strong indications that the family he lost can be reconstituted in the figures of the tawny, beautiful archer played by Virginia Hey and the wild child played by Emil Minty.

As far as one can see, Miller has everything going for him as this majestically visualized and dynamically orchestrated adventure movie builds to a climax and highballs down the stretch, with the community breaking out and making a dash for freedom, Max behind the wheel of an oil rig. Although conceived and shot quite independently, the chase that ensues is certain to inspire comparison with the truck chase in "Raiders of the Lost Ark," and it won't suffer much by the comparison either. Miller's sequence is more elaborate than it needs to be and leaves a couple of pieces of cliffhanging business hanging there, but these are minor slip-ups. The mystifying and probably self-defeating aspect of this stampeding automotive finale is the perverse decision to return Max to the solitary condition in which we found him.

While he seems to let triumph slip out of his grasp, Miller is still a prodigious talent, capable of a scenic and emotional amplitude that recalls the most stirring attributes in great action directors like Kurosawa, Peckinpah and Leone. "The Road Warrior" is full of eerily beautiful and awesome sights, and perhaps none is so strangely affecting as the vertiginous, pilot's-eye panorama that unfolds when Spence, the inventor of a gyrocopter, rescues the injured Gibson and flies him back to the safety of the refinery. Aimed straight down, the wide-angle camera discloses Gibson's bloodied, unconscious form in the foreground as a vast, ominous terrain spreads out beneath him -- the wilderness, the encampment of the barbarians and finally the tiny, precarious haven of the fort. A director who can conceive and sustain such strange, thrilling pictorial scherzos is obviously in tune with the more exalted schools of cinematic composition.