Having spent two scattershot blockbusters whetting our appetite for the fall of Anakin Skywalker (Hayden Christensen), George Lucas makes it easy to experience Star Wars: Episode III Revenge of the Sith as a rush of deliverance even if the movie itself doesn't fully deliver. From the opening space-combat sequence, in which Anakin and his mentor, Obi-Wan Kenobi (Ewan McGregor), dodge an onslaught of fireballs and enemy craft so dense that the two might be threading their fighters through needles, you can feel Lucas' boyish engagement in the galactic universe he's created. The Jedi Knights are on a mission to rescue Supreme Chancellor Palpatine (Ian McDiarmid), who has been kidnapped, and already there are hints of the conflict to come. As the two are attacked by spidery buzz droids, Anakin tries to shoot them off of Obi-Wan's ship, an act of headstrong aggression that makes you think, ''With friends like this...''
Unlike The Phantom Menace or Attack of the Clones, Revenge of the Sith unfolds with a fury of consequence. There are rousing lightsaber duels, like the one in which the skull-faced General Grievous wields four sabers at once. Yoda, with his twinkly scowl of purpose, has become such a crowd-pleasing action figure that when he coughs up solemn syntactical howlers like ''A prophecy that misread could have been'' well, forgive him almost you can. The madly detailed cityscapes raise eye candy to a dimension of comic-book awe, though I confess I miss the nearly tactile thrills generated by the original Star Wars films. Lucas' digital imagery allows for whizzy, swirling layers of technological hyperactivity, yet its lacquered gleam is just artificial enough that when a panoramic window gets smashed during a battle in the Jedi chamber, my reaction was to think, ''Gee, how will they find replacement glass that big?''
Petulant and morose, with a slightly slurry delivery, Christensen plays Anakin as if locked in a private adolescent snit fit. As political infighting rages between the forces of the Empire and the Jedi (who are portrayed in a pointed parallel with our own wartime climate as under-siege liberals fighting ostracism), Anakin is torn between two father figures: the honorable Obi-Wan and the ambiguous Palpatine, played by McDiarmid with the jaunty menace of a corporate seducer. Of course, this is really the story of how Anakin outgrows his need for masters altogether, becoming a ''dark father'' himself. Darth Vader, with his fascist armor and his morbid cosmic boom of a voice, was always an image of malevolent manhood, even if he is the emperor's lackey. Since Christensen has never come close to that level of gravitas, we're eager to see how Anakin the testy apprentice, the surly, conflicted boy, will emerge, corrupted, from the shell of his innocence.
He does and he doesn't. Anakin's journey to the Dark Side is sparked by half a dozen different motivations, none of them entirely convincing. He has a nightmare that his pregnant bride, Padmé (Natalie Portman), is going to die in childbirth, and Palpatine exploits this premonition by promising Anakin that the Dark Side will give him power over life and death. But since the ''Hold me like you did by the lake on Naboo!'' love scenes are embarrassments of cheesy acting and cheesier dialogue, they have the unfortunate effect of hinging Anakin's descent on the worst moments in the entire series.
Anakin's instincts may be noble, but when he's chosen to be a member of the Jedi Council and yet denied the title of Master, the omission inflames his rage, a development that rings jarringly false. Anakin's appointment is an unexpected honor for a young Jedi: Why would he suddenly be up in arms about not receiving the ultimate rank as well? In case that conflict doesn't do it for you, he's also been asked to spy on Palpatine, which softens him up to believe the lie that the Jedi are hatching a conspiracy.
All of this is so talky and abstract, however, that Anakin's gathering storm seems hokey from the start, a function of the fact that it's simply time for him to begin getting mad. The trouble with Revenge of the Sith is that we're never really shown what we're told about endlessly: Anakin succumbing to the temptations of power. He sulks a lot, with a bead of resentment in his eye, but his actions never take that crucial turn toward the destructive narcissism of Darth Vader. The audience has to work to make sense of his journey, but what we're really doing is putting together the script that George Lucas didn't, quite.
Beneath Anakin's slipshod motives, one senses a failure of will on Lucas' part. The Star Wars series divided the world into Good and Evil in a way that Hollywood, by the 1970s, had forgotten. But Lucas, in his by-now reflexive populism, wants to turn Anakin into Darth Vader without risking any loss of sympathy for him. The one figure in Revenge of the Sith who taps the true spirit of Star Wars is Ewan McGregor: With his beautiful light, clipped delivery, he plays Alec Guinness' playfulness, making Obi-Wan a marvel of benevolent moxie. It's certainly fun to see Darth Vader's black armor snap into place (though couldn't they have waited until Anakin's burned skin stopped smoking?), but by the end of Revenge of the Sith, it would be a mistake to confuse Lucas' tidy game of connect-the-episodes with the elemental pleasure of the series at its best: pop storytelling done effortlessly, ushering the audience into the darkness and the light.