It is the summer before Harry's third year at Hogwarts, and he has heard that it is Sirius Black (Gary Oldman), a renegade wizard, is the Prisoner of Azkaban. What Harry doesn't suspect is that Black has escaped and is coming after him. The third Harry Potter film, with a new director in Cuarón (Y Tu Mamá También), and a darker, more complex book to adapt. There is enough dark humour, spectacular effects and appealing performances to keep you trapped in the franchise. But Harry's new adventure is also ponderous and overlong, regular Potter screenwriter Steven Kloves' confusing, rambling, structurally incoherent script, in which characters appear and disappear and plot turns are never realised, keeps the door firmly closed on this private club.