Harry Potter is due to start his fifth year at Hogwarts School of Witchcraft and Wizardry. He is desperate to return to Hogwarts and find out why his friends, Ron and Hermione, have been so secretive all summer. But before he even gets to school, Harry survives a terrifying encounter with two Dementors, attends a court hearing at the Ministry of Magic and is escorted on a night-time broomstick ride to the secret headquarters of a mysterious group called the Order of the Phoenix...