Starring: Daniel Radcliffe, Emma Watson (II), Rupert Grint

7 ouf of 10 stars: Harry Potter is three-for-three with a very strong entry, Harry Potter and the Prisoner of Azkaban. A much darker tale than the first two films, Azkaban uses the sturdy frame of J.K. Rowling's book to great effect and even fleshes out its flimsier bits, making for a satisfying and imaginative film.

It would not be correct to call Azkaban Alfonso Cuaron's film, as so much overlaps from the first films, Harry Potter and the Sorcerer's Stone and Chamber of Secrets, and so much is already predetermined (the casting, some of the general look), there's not a lot of room for him to move. But what Cuaron has always excelled at has been the asides and the parentheticals in his films (the overlooked classic A Little Princess and the ultra-steamy Y Tu Mama Tambien). Here he adds inventive details and does his best to infuse some real emotion into the scenarios (this largely doesn't work). The entire filmmaking team crams each nook and cranny with something worth seeing or worth pondering, and the film moves briskly over its two hours and twenty minutes.

The plot involves the escape of convicted murderer Sirius Black (Gary Oldman) from the wizard prison of Azkaban and his search for Harry Potter (Danielle Radcliffe), a boy attempting to complete his third year at Hogwarts School of Wizardry and Witchcraft. Sirius was reported to be a follower of Lord Voldemort, and responsible for turning Harry's parents, who thought Black was their friend, over to the evil wizard's murderous plans. Harry is warned that Sirius is probably after him next which tends to make his school year a bit disrupted once again. The new Black Arts teacher is Professor Lupin (David Thewlis) who befriends Harry but appears to be hiding some hideous secret (he is). The rest of the faculty, including Snape, McGonagall, Dumbledore (a very good replacement job by Michael Gambon for the late Richard Harris) are all on the sidelines this time round as is, thank heavens, the need to make us watch an entire Quidditch match.

Filling some of the void are the Dementors, the creepy guards of Azkaban, who are trying to track down Sirius Black. They are purposefully scary and apt to be too much for the child under 10 who might have been able to deal with them well enough on the page. A cross between the Grim Reaper and a carnival balloon stuck in sackcloth they suck the happy auras off wizards unlucky enough to cross their path. It's pretty stout stuff and there isn't much let-up once they arrive.

It's tempting to label the film Harry Potter and the Onset of Puberty as all of the kids have noticeably bolted, landing on the more pleasant side of awkward. Daniel Radcliffe loses his glasses in one moment and without them he briefly presents us with a visage that doesn't look like something approved by Random House; he's kinda handsome. Rupert Grint's appearance borders on seedy as the perpetually verklempt Ron Weasley. And Emma Watson, as Hermione, is becoming a young woman.

Thewliss and Oldman manage neither to impress us, nor embarrass themselves (well, Oldman nearly does at the end with a painful exit). They're a bit like famous professors who rarely grant office hours; it's cool they're there and they lend prestige, but they aren't putting enough of themselves out there to get anything out of them.

Oddly, it's Emma Thompson playing pseudo-psychic Sybil Trelawney, an incredibly annoying character in the book, who lends a certain humor and gravity to her role.

Rowling's book gave screenwriter Steve Kloves, whose main job has heretofore been more like cutting and pasting, a lot to get through and some of it quite messy. A scene in the third act in a place called the Shrieking Shack turns into a Mexican standoff with wands. It's close to comical in the book, as one character pops in after the other, each with a revelation more wild than the person prededing them. In the film they actually get through all of the mechanizations and exposition in a much more economical fashion. A device wherein Hermione comes up with a clever plan to maximize her available hours in the day plays out better on screen than on the page as well.

The small things? A shrunken head that sounds like Bob Marley performing the conductor's job of shouting out stops in the Knight Bus. A single leaf falling oh-so-sadly to the ground (a tribute to a similar scene from Bambi?) from the Whomping Willow (a great comedic sidekick in this film). An origami swan sets to flight. These and many others aren't required for the film to get through its paces but Cuaron certainly makes sure the trip is worth the taking.