Change is in the air in Harry Potter and the Prisoner of Azkaban. Children are magically becoming adults before our eyes; trees literally shake off their autumn leaves, then pop them back on as winter snows melt. And instead of glossing over these transformations by pretending they're not there, this movie embraces change, and in the process gives us the most fulfilling Harry Potter yet. The star is not the special effects, but nature, from which all real magic comes.

The most brilliant change is the new director, Alfonso Cuaron, whose Y Tu Mama Tambien was all about such rites of passage. And while Chris Columbus should be hailed as the guy who set up this franchise and gave it its foundation, this is more real, more grounded, and a breath of pure oxygen. God is in the details and in a thousand small ways, Cuaron has given Harry life, from the natural vistas, dark woods and rainy skies -- which seem real for the first time -- to the way in which children view each other and the world, Cuaron is just what the studio wizards ordered. Part of life is death, and true to that cycle of nature, Cuaron doesn't let us off the hook. Death is lurking on the periphery in Harry Potter 3 in the form of the Dementors, ghostly beings who suck out the soul of those who get in their way. They are on hand to await Sirius Black whose escape from Azkaban Prison and vow to kill Harry sets the story into motion. Things die in this movie, as they do in any good fairy tale, including our preconceptions about good and evil.

And because every school year brings its own fresh faces to the faculty and student body, we have some new teachers at Hogwarts. As the empty-headed but wise Divination Professor Sibyll Trelawney, Emma Thompson is spot on. Though at home in Hogwarts, dizzy Sibyll is reminiscent of every New Age guru who operates out of her VW Rabbit between Yoga class and an overstuffed apartment in downtown Burbank. Standout too, though only in his short appearance, is Gary Oldman as the seriously named Sirius Black, who, it is the conceit of the film, is the bad guy. And as the on-the-nose named Professor Lupin, David Thewils is another of Harry's flawed mentors. There is even a new Headmaster Dumbledore, or at least one taking the place of Richard Harris; Michael Gambon is fine.

But most noticeable are the physical changes to the returning cast. They are growing up into sterling adults here in the Muggles-free zone. And the changes suit them. Yes, Hermione (Emma Watson) is still a know-it-all, Ron Weasely (Rupert Grint) is still a whiny Mama's boy, but their blooming romance, and the adult ways in which they take on the task of seeking and learning lessons in friendship, are what seem most magical. Rupert is becoming a handsome lad and Emma has no doubt created the job of Breast Continuity on the production. No amount of magic is as powerful as that of a young person in the midst of such change. And it's handled with charm as when Emma worries about how her hair really looks, a line that gets the film's biggest laugh later on.

And then there is Harry.

He may be 42 by the time he finishes his duties as the most widely recognized child star since Macaulay Culkin, but Daniel Radcliffe doesn't seem to mind. And neither do we. It is a tribute to the amazing inspiration that guides the fortunes of the Harry Potter franchise that Radcliffe was chosen for this role. There would have been no way to predict how the process would affect him, how physically growing up on camera would corrode or steel his virtues, but it's working. This Harry is downright noble. Gone is the wide-eyed innocence, and the childish fun of being a young wizard. The joys of winning a game of Quidditch in front of your friends has given way to more serious challenges to the laws that govern life and the responsibilities one's own powers of magic entail. Still searching for his father and mother, still on the lookout for the one person who can tell him the way home, Harry is discovering that he already knows much of what he needs to know, and is his own best mentor, and that realization is both intoxicating and frightening.

But that's what growing up is all about.

In a summer of overwrought special effects films like Van Helsing, and sledgehammer wit aimed at jaded adults in Shrek 2, Harry Potter offers just the right balance for children and grown-ups who've forgotten what being a child is like. A fairy tale from the far away lands of the English Boarding School system where magic can really happen -- if you get the right people -- and have nature on your side.

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