The listing, Harry Potter and the Prisoner of Askaban Paperback Book has ended.
Harry starts off his third year at Hogwarts rather eventfully. He inadvertently blows up his Aunt Marge, goes on the run and is then personally absolved by the Minister of Magic himself. He then learns that mass murderer, Sirius Black, is intent on killing him, and Mr. Weasley makes him promise a strange thing, that no matter what he hears he won’t go looking for Black. Confused, Harry agrees.
As he heads back to school armed with this knowledge, he learns that dementors, evil, soul-sucking creatures, have been stationed around Hogwarts for protection against Black. They effect Harry much more than the others students because of his terrible past, and he quickly resolves to learn to defend himself when he begins collapsing every time they come near. He finds a willing teacher in Professor Lupin, the new Defense Against the Dark Arts professor, who begins teaching Harry the Patronus Charm, which is the only spell that will work against the foul creatures.