Harry Potter and the Prisoner of Azkaban. (In reading order: 3)

When the Knight Bus crashes through the darkness and screeches to a halt in front of him, it's the start of another far from ordinary year at Hogwarts for Harry Potter. Sirius Black, escaped mass-murderer and follower of Lord Voldemort, is on the run - and they say he is coming after Harry. In his first ever Divination class, Professor Trelawney sees an omen of death in Harry's tea leaves . . . . . . . . .