While most students enjoy a quiet third year where they have finally reached a level of maturity and are respected by older student, Harry Potter had a school year more action pack than his last to combined. It started with the hiring of werewolf-teacher Remus Lupin, who according to teacher testimony, didn't know the first thing about his subject, Defense Against Dark Arts. 

 Lupin gave Harry special favoratism and special lessons on the Patronus charm. Harry soon learned to produce his signature stag patronus, which he used to defend himself from dementors then guarding school grounds from murderer Sirius Black, who happened to be Harry's godfather. 

 At the end of the year, Harry tracked Sirius Black down himself. Black nearly took Harry's life, but Harry was able to use his advanced magical abilities to ward him off. Black then stole a mad hippogriff and flew away, stunning Harry. Harry was nearly Kissed by Dementors, but he woke in the nick of time and bravely drove the Dementors, not only from himself, but away from the school. 

 Harry's year ended without exams, as a treat to the school after eduring the Dementors and to reward them for tolerating werewolf professer Lupin.