The first two films in the Harry Potter franchise were middling efforts; they were faithful to J.K. Rowling’s beloved books but did little to convince as films in their own right. Harry Potter and the Prisoner of Azkaban was a clear step up in caliber. Directed by Alfonso Cuarón, whose preceding film was the critically acclaimed Y Tu Mamá También, the third installment in the Harry Potter series was moody and edgier, suffused with a dark color palette and an auteur’s feeling for ambience. Cuarón memorably portrays Rowling’s Dementors, wraithlike sentinels who fill their environs with gloom and are capable of sucking out your soul. The story’s no longer just a kid’s tale.