Before Harry’s 3rd year at Hogwarts has even begun, news of a mass-murderer escaping Azkaban, the wizard jail, seeps through to Little Whinging on the Muggle news.
When Harry returns to find that the guards to Azkaban, dementors, are now guarding his school. The dementors are capable of taking all the happiness out of the room, and sucking your soul away.
After not being allowed into Hogsmeade with all the other third-years, Harry is gifted with the Maruader’s Map, an enchanted map that shows everybody in the school, whenever the user requires. Using his father’s old Invisibility Cloak and the map, Harry finds his way to Hogsmeade and sees Ron and Hermione, only to overhear a conversation between his teachers and the Minister for Magic, Cornelius Fudge.
His eavesdropping is rewarded only with Harry finding out that the why the dementors are at Hogwarts: because Sirius Black, the escaped murderer, is trying to get to Harry; that Black is Harry’s godfather and that he betrayed Harry’s parents, James and Lily Potter to Voldemort himself.
The third exciting story in the famous series, the Prisoner of Azkaban is a tale not to be missed.