It's fitting that puberty begins to trouble our young heroes just as the helmer of Y Tu Mamá También takes over directing their adventures. Wiser, more impulsive and a wee bit petulant, Harry (Daniel Radcliffe) gets more interesting as he grows up, even if his parent-slaying bête noir remains the ethereal Voldemort.
Gary Oldman is this entry's villain, an escaped con out to off our boy hero. But it's the peely-skinned, Ringwraith-alike Dementors who out-scare the giant snake from Chamber Of Secrets and lend the franchise genuine menace.
Alfonso Cuarón paints the world of Potter with grain and darkness, bringing an eerie atmosphere to Hogwarts and beyond. And writer Steve Kloves has whittled down the plot, making the streamlined screenplay less slavishly beholden to JK Rowling's page-turner.
Story and style aside, though, this is David Thewlis' film, the actor bringing a nuanced, pained intensity to Professor Lupin. He overshadows everyone except Emma Watson's sparky Hermione - - the teenage actress, like the franchise, getting better with every outing.