Order of the Phoenix

This novel begins when Harry and his cousin, Dudley Dursley, are attacked by dementors. Harry uses magic to fight them off and must attend a disciplinary hearing for underage magic. In response to Voldemort's reappearance, Dumbledore has re-activated the Order of the Phoenix, a secret society which works to defeat Voldemort's minions and protect his targets. Despite Harry's description of Voldemort's recent activities, the Ministry of Magic and many others in the magical world refuse to believe that Voldemort has returned, and are causing a smear campaign against Harry and Dumbledore.

In an attempt to enforce its version of the school curriculum, the Ministry appoints Dolores Umbridge as the new Defence Against the Dark Arts teacher of Hogwarts. She transforms the school into a quasi-dictatorial regime and refuses to teach the students to defend themselves against dark magic. She is later installed as a school inspector, and finally as Headmistress after Dumbledore is forced to flee. Harry's friends Ron and Hermione persuade him to form a secret study group and teach his classmates the higher-level skills he has learned. He also meets Luna Lovegood, an airy yet good hearted young witch with a tendency to believe in oddball conspiracy theories. He also discovers that he and Voldemort have a telepathic connection, allowing Harry to view some of Voldemort's actions.

In the novel's climax, Voldemort lures Harry into the Ministry of Magic in a plot to steal a record of a prophecy which concerns Harry and Voldemort. Harry and his friends face off against Voldemort's Death Eaters in a battle, during which the prophecy is smashed. The timely arrival of members of the Order of the Phoenix saves the children's lives, but Sirius Black, Harry's godfather, is killed in battle by Bellatrix Lestrange. In the entrance hall, Harry comes face to face with Voldemort for the fourth time in his life, but is saved by Dumbledore who engages with the Dark Lord in a ferocious duel. In the end, most Death Eaters are captured, and the return of Voldemort is confirmed within the magical world.

In the aftermath of the battle, Dumbledore explains to Harry that just before his birth, a prophecy was made saying that a child was being born with the power to defeat Voldemort. The prophecy could have referred to Harry or Neville Longbottom, but it was Harry that Voldemort chose to hunt down. Since his return, Voldemort has been determined to find out the rest of the Self-fulfilling prophecy, which Dumbledore reveals to Harry: firstly, "the Dark Lord will mark him as his equal", and that "neither can live as the other survives" – ultimately, either Harry or Voldemort will kill the other.

[Credit: Wikipedia]