Boffo boy wizard Potter (Daniel Radcliffe) rides again—this time under the yoke of helmer Alfonso Cuarón ( Y Tu Mamá También )—and the resulting kids’ yarn is zippier and more macabre than Chris Columbus’ two previous plodding productions.

“Is it true to the book?” shriek legions of fans, clutching their wands, robes, and buckets of popcorn. Yes, kids, it is, but not so slavishly that the film lacks a spark of its own. It helps that J.K. Rowling’s third book in the series is full of spooky stuff that translates beautifully to screen.

The diaphanous Dementors of Azkaban prison could look cheesy but they don’t; wisely, Cuarón shows them mainly in glimpses and long shots, enhancing their mystery. Nor do the plentiful creature effects (hippogriff Buckbeak, new animagi, and a werewolf make their debuts here) overshadow the story. The potentially corniest moment—Harry’s ride on Buckbeak’s back—dares the cynical (i.e., adult) viewer to scoff at Radcliffe’s oohs and aahs against the green-screen (reportedly Cuarón had him imagine Cameron Diaz in a thong). But the film is such a lark that it’s easy to get swept along just the same.

The best moment is a shape-shifting boggart’s emergence from an armoire as sneering Professor Snape (Alan Rickman); bumbling Neville Longbottom (Matthew Lewis) then imagines Snape with his grandmother’s fur-collared suit and handbag.

The juvenile actors perform adequately, but the treat is the star lineup of British thesps. Emma Thompson is a riot as myopic witchy-woman Professor Trelawney, and Mike Leigh alumnus David Thewlis makes a dashing Professor Lupin. Less fortunate is Michael Gambon, who succeeds the late Richard Harris as Hogwart’s headmaster Dumbledore, for despite his best efforts he lacks the former’s gravitas; the absence is palpable.

I won’t even bother explaining the plot of this latest installation for those two or three non-initiates to the Harry Potter universe. You’d be lost anyway. The film doesn’t bother with much exposition—there are no flashbacks, for example. It just chugs along briskly, riding a wave of wonder and enthusiasm. The third act seems overlong due to Rowling’s introduction of a time-travel device, and young viewers may exit the theatre with crossed eyes and sore butts. But they’ll have gotten a full ride for their ticket.

HARRY POTTER AND THE PRISONER OF AZKABAN (3-1/2 stars)
Directed by Alfonso Cuarón
Starring Daniel Radcliffe, Emma Watson, Rupert Grint, Gary Oldman, Michael Gambon, David Thewlis, Alan Rickman, Maggie Smith
(Rated PG, 136 min.)