In Harry Potter and the Order of the Phoenix, Harry begins his fifth year at Hogwarts feeling isolated and ignored by the Ministry of Magic, which denies Lord Voldemort's return. Under the tyrannical rule of new Defence Against the Dark Arts teacher, Dolores Umbridge, Harry secretly teaches his friends defensive magic in Dumbledore's Army. Harry's vision of a door at the Ministry of Magic leads him to a confrontation with Voldemort, culminating in a duel between Voldemort and Dumbledore and the Ministry's forced acknowledgment of Voldemort's return. 
Key events and themes:
  • The Ministry's Denial: 
    Following Voldemort's resurrection in the previous book, the Ministry of Magic, under Minister Fudge, refuses to believe it and actively suppresses the truth, leading to public denial of the threat. 
  • Umbridge's Reign: 
    Dolores Umbridge is appointed by the Ministry as a "High Inquisitor" at Hogwarts, where she implements brutal and tyrannical measures, including banning extracurricular activities and punishing students, further isolating Harry. 
  • Dumbledore's Army (D.A.): 
    In defiance of Umbridge, Harry, Ron, and Hermione form Dumbledore's Army to teach students defensive magic, as Umbridge refuses to teach it to them, and the students become increasingly aware of the growing darkness. 
  • The Ministry of Magic Battle: 
    Harry, Ron, Hermione, and their friends venture to the Ministry to save Sirius, but they find themselves facing Voldemort's Death Eaters. 
  • The Prophecy: 
    A crucial prophecy about Harry and Voldemort is revealed at the Ministry, confirming that "Neither can live while the other survives" and that Harry must be the one to defeat Voldemort. 
  • Voldemort's Return: 
    The final confrontation at the Ministry of Magic leads to the public acknowledgment of Voldemort's return and the beginning of open warfare between the Ministry and Voldemort.