Harry Potter and the Prisoner of Azkaban follows Harry's third year at Hogwarts, where he must evade Sirius Black—an escaped, maniacal follower of Lord Voldemort. Aided by new teacher Remus Lupin and a time-travel device, Harry masters advanced defensive magic and uncovers the dark truths surrounding his parents' betrayal.Key Details & Plot PointsThe Escape: Sirius Black breaks out of the wizarding prison Azkaban. The magical world believes he is hunting Harry to finish off the Dark Lord's unfinished business.The Dementors: To protect the school, Azkaban's soul-sucking guards are stationed around Hogwarts. Because of Harry's traumatic past, these creatures affect him more severely than anyone else, forcing him to learn the Patronus Charm.The True Betrayal: Alongside his friends Ron and Hermione, Harry discovers that Black is actually his innocent godfather. The true culprit was Peter Pettigrew, a servant of Voldemort who had been hiding as Ron's pet rat, Scabbers.A Darker Tone: This installment marks a transition from children's mystery to a darker, more complex magical reality, as Harry learns difficult truths about his parents' past and must grapple with the concepts of justice and revenge.