Harry Potter and the Order of the Phoenix, Volume 5

The beginning of darkness.

Harry must spend his solitary summer break at Number 4, Soi Prewet, amid feelings of neglect from his friends and the magic world, until he is raided by Dementors in a Muggle residential area, forcing him to use a guardian spell to survive; this incident results in his almost expulsion from Hogwarts School and having to go to Wicengamot Court.

Return of the Order of the Phoenix

Harry is taken to Number 12 Grimmold Plaze, the secret command of the "Order of the Phoenix," a group founded by Albus Dumbledore against Lord Voldemort; however, the Ministry of Magic instead rejects Voldemort's return and sees Dumbledore and Harry as liars who want to create chaos.

The Dark Ages in Hogwarts

At the start of the semester, the Ministry sent Dolores Umbridge as a teacher of the Defence Against the Dark Arts to monitor and control Hogwarts. She used authoritarian power to ban magic in the classroom, causing Harry, Ron and Hermione to decide to form a secret group called the "Dumbledore Army" (D.A.) to practice combat on their own.

Vision and tragedy

Harry began to dream of strange events through Voldemort's eyes until he had a vision that his godfather, Sirius Black, was being tortured at the Ministry of Magic, so he and a group of friends rushed to help, but found that that was the trap Voldemort had set to lure Harry to pick up the "prophecy."

Conclusion

Battle at the Enigma Division: There was a violent clash between a D.A. member and a group of Death Eaters before a member of the Order came to help.

Losses: Sirius Black dies during the battle, causing great sadness to Harry.

Revealed Truth: Voldemort made a public appearance, forcing the Ministry to accept the truth, and Harry realized the content of the prophecy: "One cannot live if the other survives."

Anecdotes: This is the longest of the seven books and the most profound transmission of adolescent emotions and loss encounters.