OK; let's say you're James Cameron. You're humming along as a reliably successful filmmaker, with movies like "Aliens" and "Terminator 2: Judgment Day" under your belt, when all of a sudden your mad gamble, a $200 million popcorn flick about an unsinkable boat that apparently wasn't, pays off beyond everyone's wildest dreams. You earn gobs of money, win a few Academy Awards, and crown yourself "the king of the world." At this point you can write your own ticket. But when you've already made the highest-grossing film of all time, what can you possibly do for an encore? Well, now we know: you go away for a while - at least 10 years; people were totally sick of Your Majesty - and develop wondrous, game-changing software that will allow you to remake "Dances with Wolves." In space.

As you may have noticed, "Avatar" is finally here, bringing with it buzzy hype and titanic expectations. A science-fiction epic 15 years in the making - Cameron has been quoted as saying that he was waiting for the technology to catch up with his vision - "Avatar" takes place in 2154 on Pandora, a moon of - oh, never mind. There is plenty of detailed backstory that, while impressive in its thorough intricacy, non-geeks may find overwhelming. "Avatar" stars the relatively unknown Australian actor Sam Worthington (he was in "Terminator: Salvation" and will soon headline the new "Clash of the Titans") as Jake Sully, a paraplegic former Marine who travels the light-years from Earth to Pandora in order to complete a job started by his late scientist brother.

Showcasing yet another one of those thinly veiled metaphors for American imperialism, Pandora is home to an extremely valuable substance of ambiguous purpose called unobtainium, and the greedy Earth people would like to mine it out from under the unsuspecting feet of Pandora's inhabitants. A long, lean race of beings that look like sexy blue tabby cats, the Na'vi worship nature and warily tolerate the presence of the humans who have found a way to combine their DNA with Na'vi DNA and move through their environment as halflings. Under the direction of Dr. Grace Augustine (Sigourney Weaver, with occasional flashes of Ripley), these avatars interact with the Na'vi and learn about their culture. But the military-industrial complex side of the operation, as personified by the moustache-twirling Stephen Lang ("Public Enemies") and an ill-used Giovanni Ribisi, just wants its oil - er, unobtainium - no matter the damage to the planet.

His nimble avatar affording him the breathtaking freedom he lost along with the use of his human legs, Jake's job is to both assimilate with the Na'vi under the tutelage of Dr. Augustine and report back to the powers-that-be over the accessibility of the unobtainium. It's through Jake's blossoming friendships with his Na'vi hosts - especially the fiery, beautiful Neytiri (Zöe Saldana from "Star Trek" in all her virtual glory) - that "Avatar" begins channeling other films. First we get echoes of Terrence Malick's "The New World," with the John Smith-esque outsider taken under the loving, intelligent wing of the Pocahontas-like princess, then it's Costner's Oscar-winner all the way, when the outsider predictably goes native and must help his adopted people stave off the narrow-minded interlopers. But there is much more firepower on Pandora than there ever was on the prairie.

One day, if the gods smile upon us, James Cameron will accept his shortcomings as a writer; he creates dialogue with all the insight of a lovestruck tween, and his messages concerning the environmental protection and misguided American entitlement (for and against, respectively) are beyond heavy-handed. (On the plus side, Cameron certainly does seem to appreciate strong women.) This lack of subtlety wouldn't be a crime if our eye-rolling didn't distract us from the mindblowing images on the screen, because as a purely visual storyteller, Cameron is in a league of his own. Unfolding in a primitive yet futuristic rainforest, lushly green by day but at night aglow with the neon pinks and blues of the naughtier section of Spencer's Gifts, "Avatar" is like nothing you've ever seen. Taking the art and science of motion-capture to the next level, Cameron has created from scratch an entire world that rarely seems fabricated, and it's a testament to the talents of his nameless, faceless, button-thwapping minions that 160 minutes fly by.