Harry Potter and the Twin Sister's Doppelganger

For twelve years, a prisoner by the name of Sirius Black was detained in the eerie fortress of Azkaban. Accused of murdering thirteen people with a single curse, he was rumored to be the heir of the Dark Lord, Voldemort. But he's not alone. With him is another prisoner who was convicted of killing a number of incident people while on her journey in the hunt for Annie and Harry Potter to complete Voldemort's master plan... the rise of the Dark Lord. Now he and this mysterious prisoner have escaped, leaving behind two clues as to where they might be headed. In addition, the Azkaban guards heard Black mumbling in his sleep, "They're at Hogwarts... they're at Hogwarts." Now, Harry and Annie Potter's safety is in jeopardy and the walls of the Hogwarts School surrounded by their friends can't save them from a potentially dangerous threat. Among other things, there may be a traitor in their midst.