Diary of a Discovered Girl

Holly Potter is the twin sister of Harry Potter, though only her brother and the Weasleys know it. She and the Boy-Who-Lived are returning to their third year at Hogwarts... but her cover might be blown when Remus Lupin recognizes the daughter of one of his best friends. Set to 'Prisoner of Azkaban.' Third in a series. Rewritten and updated.