Harry (Daniel Radcliffe), Ron (Rupert Grint) and Hermione (Emma Watson) have returned to Hogwarts for their third year, but there is a shadow hanging over Harry: dangerous serial killer Sirius Black (Gary Oldman) has escaped from the Wizards' prison, the Azkaban Fortress - and he wants revenge for the death of his master, Voldemort. As myth, magic and teenage hormones combine to weave their dark spell, Harry uncovers a few more crucial secrets about his mysterious past.