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 … But perhaps most terrifying of all are the dementors patrolling the school grounds, with their soul-sucking kiss.