Harry Potter and the Prisoner of Azkaban

Harry Potter is with Dursleys for the summer, learning to do more spells, and awaits an imminent visit from Uncle Vernon's sister Marge. Harry loses his temper when Marge insults his family, and unintentionally causes her to inflate and float away. Harry flees, as he expects to be punished for performing magic outside of school. The Knight Bus appears and takes Harry to the Leaky Cauldron where Minister for Magic Cornelius Fudge tells Harry he will not be expelled. Harry learns that Sirius Black, who is said to be a supporter of Lord Voldemort, has escaped from Azkaban and that Black will likely come after him.

Harry journeys to Hogwarts with his best friends Ron and Hermione. On the Hogwarts Express train, they share a compartment with the new Defense Against the Dark Arts teacher, Remus Lupin, who is sleeping when they enter the compartment. Abruptly, the train is stopped and a Dementor boards, searching for Black. Harry faints when the Dementor enters their club house, but Lupin awakens and repels the Dementor after hearing a woman-like scream. At school, Albus Dumbledore informs the Hogwarts students that the Dementors have been set as a guard around the school grounds as a protection against Black. In addition to Lupin, Hagrid is announced as the new Care of Magical Creatures teacher. Lupin's lessons prove enjoyable; he teaches useful spells and helps less confident students like Neville. However Hagrid's class does not go to plan; on the first day, Draco Malfoy deliberately provokes the Hippogriff Buckbeak into attacking him. His father Lucius Malfoy successfully has Buckbeak sentenced to death.