In the third book, Harry Potter and the Prisoner of Azkaban, we once again find Harry Potter spending an unhappy summer with his guardians, the Durselys. When his Uncle Vernon’s sister insults him one too many times, Harry becomes angry, causing her to blow up and drift to the ceiling like a balloon. Not wanting to get in trouble, and afraid of being kicked out of Hogwarts for practicing magic at home, Harry runs away and takes the Knight Bus to Diagon Alley.
Harry gets a room at the Leaky Cauldron, where his friends, the Weasleys, are also staying. While there he overhears Mr. and Mrs. Weasley mention Sirius Black, a murderer who escaped from Azkaban, the wizard’s prison. They wondered if they should warn Harry about his escape.
Harry once again begins an enjoyable, but adventurous year at Hogwarts. His friend Hagrid is teaching the “Care of Magical Creatures” class and isn’t very good at it. During the first lesson, Draco Malfoy provokes Buckbeak the hippogriff, and the hippogriff attacks him in return. This doesn’t bode well for Hagrid or Buckbeak as Draco’s father, Lucious Malfoy, files a complaint with the Ministry of Magic.
Harry also has a problem with Dementors, the Askaban prison guards. They’re guarding Hogwarts, making things tough for Harry. After Sirius Black escaped from prison, it’s feared and speculated he’s coming for Harry. Harry is soon to learn Sirius Black is the one responsible for his parents’ death, for he’s the one who tipped off Lord Voldemort regarding the Potter family’s whereabouts that fateful night. A good family friend, Peter Pettigrew and many innocent muggles were also killed in the processs. Harry vows to avenge his parents.
On Christmas Harry receives a special present, a Firebolt racing broom. But who sent it? Hermione suspected it was from Sirius Black and alerted Professor McGonnagall, who sent it for testing. Harry and Ron stopped speaking to Hermione after that.
The Marauder’s Map
Fred and George Weasley present Harry with a Marauder’s Map, enabling him to see who is walking around Hogwarts at any given time. With his map and his invisibility cloak, Harry can go anywhere at Hogwarts without anyone being the wiser.
One day while looking at the map, Harry sees Peter Pettigrew walking the grounds. How could this be, if Peter Pettigrew is dead?
Happenings around Hogwarts
Other happenings around Hogwarts: Ron’s rat, Scabbers, disappears and Ron suspects Hermione’s cat, Crookshanks, Harry excels at Quidditch thanks to his Firebolt, and Hermione finds time to double up her course load, but no one knows exactly how she does it. Also, the new Defense Against the Dark Arts teacher is Professor Lupin, who, unbeknownst to the students, is a werewolf.
Buckbeak the hippogriff is sentenced to death and the friends visit Hagrid to see how he’s faring. Along the way, they find Scabbers, whom Crookshanks chases to the base of a Whomping Willow tree where a large, black dog is guarding the entrance to a passageway. The dog drags Ron inside. Harry and Hermione chase the dog, and find themselves in “The Shrieking Shack,” a haunted house. The friends soon learn the shrieking isn’t from ghosts, but it’s where Professor Lupin goes when he change over to a werewolf.
The dog turns out to be Sirius Black, whom Harry learns isn’t a murderer, and didn’t betray Harry’s parents. Black is Harry’s Godfather and legal guardian. His good friend Professor Lupin confirms this. Black and Lupin explain it was Peter Pettigrew who offered the betrayal, and he isn’t dead either. He’s alive and transfigured as Ron’s rat Scabbers! Unfortunately, the rat escapes.
The Dementors capture Black and lock him in a tower at Hogwarts to await transport back to Azkaban. With Black once again in custody and Buckbeak facing the chopping block, the friends set a plan in motion. Using the time-turner Hermione utilized to help her with her course load, they rescue Buckbeak and Black. Black flies away on Buckbeak, another crisis averted. For now.