Harry Potter and the Prisoner of Azkaban

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 .