It may be worth nine bucks to see the great young British actress Keira Knightley as a kill-crazed, blood-drenched pagan Tinker Bell, a pixie sprite with a battle ax chopping and hewing left and right. She bends it like Beckham with several pounds of cold steel and you think: Hmmm, that's a young lady with spunk!

But if Knightley's warrior Guinevere is absolutely the best thing in "King Arthur," it's not the only delight. The film boasts all the hallmarks of the '50s historic epic save the presence of Tony Curtis: battles galore, tons of rolling mist standing for the vapors of myth, cool castles, gross Germanic villains, nobility, sacrifice, mud, sweat, tears and death, with less gore than one might expect, as the movie has been engineered to a PG-13 rating.

And the film has a gimmick. This isn't your father's Knights of the Round Table song resung for the umpteenth time but a whole new tack into the material. The conceit is to locate the authentic Arthur, not the Lerner-Loewe Welshman yakkety-yakking "Camelot" to Julie Andrews amid the sunlight of a suspiciously over-illuminated Dark Ages. No Lancelot-Arthur-Guin triangle, no sword in stone, no Merlin the Magician, no Mordred the bad boy.

Instead the production is located in the 500s, when a crumbling, shrinking Roman empire is retreating from its farthest flung outposts, leaving chaos and carnage in its wake. One of the farthest flung of those outposts is Hadrian's Wall, separating Roman Britannia from pagan Britannia. There, a noble Romano-Brit officer named Arthur (Clive Owen, kingly and powerful) attempts to deal with the coming madness, made all the more threatening by the approach of yet a third antagonist, the forces of Saxony, blond, brutish invaders from Germany who threaten to overcome the island and turn it, er, Anglo-Saxon.

So one point the movie makes almost incidentally is that nobody comes from where they are, and that everybody comes from somewhere else. Many of us are slavish admirers of what's called Anglo-Saxon culture as if it were the indigenous culture of Britain and the West, but it wasn't. The Saxons were just another, earlier wave of invaders, and like all invaders their weapons were terror and rape. Stellan Skarsgard, playing the Saxon king Cerdic, looks like Yosemite Sam with a serious case of constipation.

Anyhow, in the fight to repel the invaders, Arthur has his knights. But Lancelot, Gawain, Tristan and so forth are not fair-haired Etonians in search of Christian purity. They are Sarmatians -- that is, Central European mercenaries who have been compelled by the Romans to put in 15 years' service. Their enlistment is about up, and a return to the steppes is haunting their imaginations, as is the pleasure of at last giving up the perpetual state of war in Britannia in which they've lived. In the language of today's army, they're short.

In other words, the movie offers what might be called the Arthurian Ur-text: a vision of the original reality, now long-forgot and all but irrecoverable, that was later gilded by more romantic tellers from other times and traditions, until it became so glamorized it had lost all contact with the harsh brutality of the real.

That's the theory. In practice, "King Arthur" basically encompasses two stories, somewhat awkwardly conjoined. The first is of a rescue mission that Arthur and his knights must partake, even though all have been promised release from obligation, to rescue a Roman nobleman living beyond Hadrian's Wall and thought to be in danger. As always, politics intrudes. The big shots in Rome don't care about this fellow but about his son, a favorite of the pope (who at this time is more powerful than the emperor). This initial story almost feels like a reprise of director Antoine Fuqua's last film, the underrated "Tears of the Sun," in which a U.S. Navy SEAL team was inserted into a civil war (in Africa) to extract a vulnerable citizen. In "King Arthur," the knights are the SEALs of A.D. 550, elite warriors with highly refined combat skills. It's on that mission that they encounter the teenage Guinevere, who has been captured by the Roman nobleman. She's the daughter, it turns out, of the tribal leader Merlin, a longtime antagonist of Arthur.

But he sees that the pagans -- they're called Woads here -- and the Romans can make common cause against the encroaching Saxons. And indeed, it is thought that the one true Arthur did such a thing: He unified Roman and Celtic troops and faced the Saxons 12 times, finally at the Battle of Badon Hill, where he turned them back and won for "civilized" Britain a 40-year respite, which might be seen as the antecedent of the storied peace and justice of Camelot, however brief it was.

In any event, as Fuqua tells the tale, the second half of the film is much stronger. Arthur must put away his blood enmity with the Woads and form an alliance with them to fight the Saxons, even as the perfidious Romans (personified by a smarmy bishop) are fleeing for their lives.

As he has proved many a time, Fuqua is a superb action director, and he always finds an unseen spectacle around which to build his big action set pieces. One recalls the famous Battle on the Ice of Sergei Eisenstein's "Alexander Nevsky" as the knights -- plus Guinevere, a gifted archer -- face a mass of Teutons charging across a frozen river. I'm as sick of computer imagery as you are, but the legerdemain by which the ice cracks and sends the proto-Nazis to a cold, watery grave is masterful.

The final fight pitches the fire and strength of the combined Arthurian-Woad alliance against the Germanic throngs. It's beautifully filmed as the skies fill with fire arrows, like SAMs rising against our jets over Baghdad in the recent fracas, and the forces close and clash, and the delicate Knightley goes all Samurai on her opponents, while atop their horses the surviving knights function like M-1 tanks raking through the battlefield.

You might fault the eternal cliche by which, in the middle of thousands of fighters, the two kings locate each other and settle their differences steel on steel, as the minions around them cooperate by clearing a nice little free space. On the other hand, you might as well just sit back and enjoy the fight.

Fuqua has a real weakness for calendar art compositions and I would argue that this was kitsch, except that I have the same loathsome weakness. So a lot of "King Arthur" is a kind of macho battle porn of posture, weapon and uniform: The knights are forever rearing up their steeds before charging, pennants flapping behind them, long swords drawn and glistening, armor alight with the illumination of the battle fires, all this in rapturous slo-mo, all of it framed and romanticized even further by the ghostly layers of mist floating everywhere. If this is the sort of thing you like, you're really going to like it here.

I wish the film were technically -- oh, what's the word? -- "better." We don't really get much sense of personality beyond archetype, and for a movie that pretends to a higher realism, it's still plenty jammed up with macho bluster and romanticism. Guinevere and Arthur? Well, not a love story for the ages as they're both so busy slashing and bashing they don't have much time to relate. Knightley is probably too good an actress for this sort of thing, though she makes a great battle faerie. Ioan Gruffudd who plays Lancelot, the smartest and most loyal of the knights but also the most conflicted, really doesn't feature in the workings of the story. He's just there, and more attention goes to the sexy beast Ray Winstone as someone named Bors, more man-mountain than cavalry trooper, who gets most of the best lines.

King Arthur (125 minutes, at area theaters) is PG-13 rated for intense battle scenes.

Keira Knightley as Guinevere battles Saxons alongside Clive Owen's knightly Arthur.Ioan Gruffudd, left, is Lancelot, the smartest and most loyal of the knights, and Clive Owen is a powerful King Arthur.