Harry Potter 5: Order of the Phoenix

"Harry Potter is stuck with the Dursleys in Privet Drive for a long, hot summer. Sirius Black has told him to lie low - but how can he, when the Darkest wizard in history is gathering strength, and the wizarding authorities seem unwilling to do anything about it? Harry knows that Voldemort's Dark Forces will find him, wherever he is.
Two Dementors soon bring their death-cold breath to Little Whinging, and Harry uses magic to save his cousin Dudley's life. Expelled from Hogwarts and accused of illegal magical activity, Harry discovers the secret domain of the Order of the Phoenix - and that maybe he's not alone in his battle after all."