Harry Potter is spending another horrible summer with his dreadful Aunt Petunia and Uncle Vernon when a group of evil spirits called Dementors stage an unexpected attack on Harry and his cousin Dudley. After he uses magic to defend himself and Dudley, an act that later gets Harry expelled from Hogwarts, he is visited by a group of wizards and Madeye Moody and the is whisked off to number 12, Grimmauld Place, London.
Number 12 is the home of Harry's godfather, Sirius Black, and the headquarters of the Order of the Phoenix. The Order is a group of witches and wizards, led by Hogwarts headmaster Albus Dumbledore, dedicated to fighting the evil Lord Voldemort and his followers.
The Order is forced to operate in secrecy, outside of the jurisdiction of the Ministry of Magic, which is headed by the dense and corrupt Cornelius Fudge. Fudge refuses to believe that Lord Voldemort has returned. Harry, who witnessed Voldemort's return the previous June and was tortured and nearly murdered by him, is suffering from nightmares about what has happened to him. He is also angry with those he is close to, especially Ron and Hermione. Harry used magic to fight off the dementors, and since underage wizards are not permitted to use their wands outside of school, he must face a disciplinary hearing at the Ministry.
'You are sharing the Dark Lord's thoughts and emotions. The Headmaster thinks it inadvisable for this to continue. He wishes me to teach you how to close your mind to the Dark Lord.' ' Dark times have come to Hogwarts. After the Dementors' attack on his cousin Dudley, Harry Potter knows that Voldemort will stop. After the Dementors' attack on his cousin Dudley, Harry Potter knows that Voldemort will stop at nothing to find him. There are many who deny the Dark Lord's return, but Harry is not alone: a secret order gathers at Grimmauld Place to fight against the Dark forces. Harry must allow Professor Snape to teach him how to protect.
With Dumbledore's help, Harry is cleared by the Wizengamot and permitted to return to Hogwarts School of Witchcraft and Wizardry.