MOVIE SUMMARY: It's the summer before Harry's third year at Hogwarts. His Aunt Marge comes to stay with them for awhile and Harry, in order to get his permission form to go to the wizard town of Hogsmeade signed, he is civil to her. However, he loses his temper on the last night and Marge is inflated. Harry runs away thinking he is expelled from school for using magic, and sees a dog watching him from an alley. He is fightened and trips over his trunk and accidently signals the night bus, which he boards and learns that Sirius Black is an escaped wizard. He arrives at the Leaky Cauldron where the Minister of Magic is waiting for him and tells him that he isn't expelled and that as long as he stays in Diagon Alley he doesn't have to go back to the Dursley's. During the last few days of the holiday, Ron and Hermione show up and on the night before the trip back to Hogwarts, Harry hears Mr. and Mrs. Weasly talking about how Sirius Black is after Harry. On the Hogwarts express the next day Harry meets his new Defense Against the Dark Arts professor, Remus Lupin, and his worst fear, the Dementors. When the trio arrive at Hogwarts, they find that Hagrid is the new Care of Magical Creatures professor. Ron and Harry notice that Hermione is somehow taking two or three classes at the same time. Then something that Harry didn't expect would happen did happen when he and his team played Hufflepuff. Somehow the Dementors made Harry fall to the ground, after hearing a evil voice and his mother begging. Harry recovers in the hospital wing. He learns about his broom and sees what is left of it. Harry now seems to have a major problem at hand, when Sirius Black breaks in attacking Portrait Lady, and the dementors. With the help of Prof. Lupin Harry learns the Patronus Charm. Harry learns in the end that Sirius Black is innocent and he will stop at nothing to rescue him from the dementor's kiss and the Ministry of Magic