The dreaded fortress of Azkaban held an infamous prisoner named Sirius Black. Sirius Black was convicted of killing thirteen people with a single curse. He was said to be the heir to the Dark Lord, Voldemort. Suddenly he escapes, leaving only two clues as to where he might be headed. The Azkaban guards heard Black muttering in his sleep, "He's at Hogwarts . . . he's at Hogwarts." So Harry Potter isn't safe. He is at his magical school with his friends. Harry Potter goes on an adventure.