Impressive Mexican filmmaker Alfonso Cuaron is new at the helm, and the popular Potter saga is as magical and adventurous as ever. If anything, "Harry Potter and the Prisoner of Azkaban" is just a smidgen darker than its predecessors, and deliciously foreboding.

After taking one year off (probably to avoid butting heads with the eagerly awaited end of "The Lord of the Rings" trilogy), "Potter" is back with no momentum lost.

The Harry Potter of "The Prisoner of Azkaban" is growing more confident and assuming more easily his place as an important figure in the world of wizards. (Not coincidentally, actor Daniel Radcliffe is also growing appealingly in the role.)

As the film opens, Potter finally serves up some just desserts to the horrible family of mean-spirited muggles who keep him a virtual prisoner during his summer vacations.

And, once back at Hogwarts, he easily assumes his leadership role. There's also plenty of opportunity for his friend, Hermione (Emma Watson), to do her smart and spunky thing. And then there's lovable Ron (Rupert Grint), who struggles mightily to keep up with his intrepid friends.

The adventures of the third term revolve around a frightening fact: Sirius Black (Gary Oldman) has escaped from prison. Harry's been told Black was an old friend of his late parents who betrayed them, leading to their deaths. Now he's after Harry.

To protect the youngster (and his school), special guards are sent to surround Hogwarts. Ghostly figures known as Dementors are proof positive that the cure is sometimes worse than the disease. To identify suspects, the Dementors suck out souls, which we guess is a most unpleasant experience.

Though Harry must be on the lookout for Black, he has his regular array of classes in divining and spell-casting and magical animals, etc. The most enjoyable are taught by Hagrid, the beloved school gamekeeper who's been upgraded to the classroom. He teachers his pupils about magical animals, particularly the Hippogriff, a mythical combination of a horse and a giant eagle. The sequences involving the creature are among the most delightful in the film.

Michael Gambon does a credible job replacing the late Richard Harris as headmaster Albus Dumbledore. (His role here is small; a good way to gradually replace a beloved performer.) Emma Thompson and David Thewlis add humor and texture as the school's two newest professors.

Cuaron diverse credits include an evocative version of "A Little Princess," as well as the sexy, daring "Y Tu Mama Tambien." Here he takes an energetic but spookier approach to the material, introducing werewolves and talking shrunken heads, along with a generally darker texture.

Fear not; Cuaron never oversteps the established PG boundaries. He remembers the youthful nature of Potter's chief audience. On the other hand, he respects his audience's spirit and intelligence. The result is the continuing maturity of one of Hollywood's most magical film franchises. And fans will be pleased to learn that according to imdb.com, filming has already begun on the next film in the series, "Harry Potter and the Goblet of Fire," due in 2005.