For twelve long years, the dreaded fortress of Azkaban held an infamous prisoner named Sirius Black. Convicted of killing thirteen people with a single curse, he was said to be a dedicated follower of the Dark Lord, Voldemort. Now he's escaped. And the Azkaban guards heard Black muttering in his sleep, "He's at he's at ; Is he coming for Harry? Harry Potter isn't safe, not even within the walls of his magical school, surrounded by his friends. Because on top of it all, there may be a traitor in their midst.