"Till now there's been no magic for Harry Potter. He lives with the miserable Dursleys at number four, Privet Drive. His room is the cupboard under the stairs, and he hasn't had a birthday party in eleven years. But then a mysterious letter arrives by owl messenger: a letter with an invitation to an incredible place called Hogwarts School of Witchcraft and Wizardry. And there he finds not only friends, flying sports on broomsticks, and magic in everything...

For twelve long years, the dread fortress of Azkaban held an infamous prisoner named Sirius Black. Convicted of killing thirteen people with a single curse, he was said to be the heir apparent to the Dark Lord, Voldemort. Now he has escaped, leaving only two clues as to where he might be headed: Harry Potter's defeat of You-Know-Who was Black's downfall as well. And the Azkaban guards heard Black muttering in his sleep, "He's at Hogwarts . . . he's...