The escape of renegade wizard Sirius Black from a hellish incarceration is the plot mechanism that drives "Harry Potter and the Prisoner of Azkaban," the third in a never-ending series of adaptations of J.K. Rowling's phenomenally popular novels.
But the more pressing issue is whether the film's talented director, Alfonso Cuaron, can escape the prison constructed for him by the man who directed the first two, Chris Columbus. The answer is yes, but just barely and, true to the tradition of adventure yarns, only at the last minute.
Actually, make that the last 60 minutes. For the final hour of the two-hour-and-21-minute "Azkaban" is the closest any of the films has gotten to capturing the enormously pleasing essence of the Potter books.
The fact that it took Cuaron, who last did the exceptional "Y Tu Mama Tambien," so much time to break free says a lot about how much individuality and personal expression any director, no matter how gifted, can bring to a moneymaking franchise of such fecundity that it has to be shielded from risk at all costs.
That's why even though Cuaron -- with "A Little Princess" on his resume -- was one of Rowling's top choices to do the first Potter films, he did not get the job. Warner Bros. instead turned to the unapologetically mainstream Columbus, an unadventurous Hollywood apparatchik who ended up re-creating all the detailed surface and none of the underlying magic of the Potter books.
Still, that soulless fidelity went down well enough to earn the first two films some $1.8 billion worldwide, enough to ensure that any director would be too straitjacketed by what had come before to put his own stamp on the material and make a truly great film.
So Cuaron, who used the same writer (Steven Kloves), production designer (Stuart Craig), composer (John Williams) and trio of leads as the previous two films did, ended up putting the best face on a problematic situation.
"I think Chris created a very elegant universe," he told one reporter. "It would have been not only irresponsible but also stupid to come and say, OK, just for the sake of change, let's change all this stuff that is working fantastically well."
And even if Cuaron had wanted to, Columbus had installed himself as a producer on "Azkaban" with a particular goal in mind: "I wanted to make sure that the film didn't stray too far from the world the audience and the fans have sort of fallen in love with over the course of the first two movies," he told The Times' John Horn last year.
Thanks, Chris, we needed that.
Those three leads (Daniel Radcliffe as Harry, Emma Watson as Hermione, Rupert Grint as Ron) play characters who are now 13, an age when anger and frustration are more publicly expressed. One of the benefits of Cuaron's direction, his expertise with younger actors, means that the constant determination and occasional fury exhibited by the characters, especially Harry and Hermione, are completely convincing.
And Harry, raging hormones aside, has a good deal to be angry about as he returns for his third year at Hogwarts. That pesky wizard Black (Gary Oldman), imprisoned for betraying Harry's parents to the dread Voldemort, has apparently escaped, with the termination of our young hero at the top of his to-do list.
Plus, with only defense-against-the-dark-arts teacher Professor Lupin (David Thewlis) on his side, Harry has to deal with the black-robed Dementors, those soul-destroying, kiss-of-death-bestowing Azkaban prison guards who look to be the direct descendants of the similarly robed and equipped Nazgul, who gave Frodo such a hard time in "Lord of the Rings."
Rowling's "Azkaban" had a darker cast than the first two Potter books, and it's fortunate that Cuaron is a convincingly edgy director, someone for whom a sense of genuine unease feels natural and appropriate.
Also helpful is Cuaron's ability to work with fully grown performers as well as the young adult variety.
Doing especially good work are the key people new to the series. Oldman exhibits a delicacy he hasn't always shown with the character of Sirius Black, and Thewlis, best remembered for starring in Mike Leigh's "Naked," brings a mature and compassionate presence to Professor Lupin. Between the two of them they do the best, most realistic acting the Harry Potter films have offered to date.
The rest of "Azkaban's" new casting is regrettably uneven. Michael Gambon, through no fault of his own, does not have the gravitas the late Richard Harris brought to the role of Hogwarts headmaster Professor Dumbledore. Emma Thompson has been either allowed or encouraged to painfully overact as divination professor Sibyl Trelawney, and Julie Christie's cameo as a Hogsmead tavern functionary is even briefer than her appearance in "Troy."