The Order of the Phoenix is a secret organization founded by Albus Dumbledore (Michael Gambon). They inform Harry (Daniel Radcliffe) that the Ministry of Magic is not acknowledging that Lord Voldemort (Ralph Fiennes) is back. At the Order’s headquarters, Harry’s godfather, Sirius Black (Gary Oldman), mentions that Voldemort is after an object he did not have during his previous attack.
Once they are back at Hogwarts, Harry learns that the Minister for Magic Cornelius Fudge (Robert Hardy) has appointed a new Defence Against the Dark Arts professor: Dolores Umbridge (Imelda Staunton). She and Harry immediately have beef, and she punishes Harry for his “lies” by forcing him to write “I must not tell lies” with a magic quill that scars his hand. When Ron (Rupert Grint) and Hermione (Emma Watson) notice Harry’s scars they are like hell no, but Harry doesn’t want to go to Dumbledore because he’s Harry Potter and he will save the world anyway and who anyway has distanced himself from Harry since the summer. As Umbridge’s control over the school increases to like the HBIC Cheryl of Hogwarts, Ron and Hermione help Harry in forming a secret group to train students in defensive spells ’cause that’s apparently what we do these days, calling themselves “Dumbledore’s Army” even though Dumbledor hasn’t given to craps about the students over the year. Umbridge recruits the Slytherin students to expose the group. Meanwhile, Harry and Cho Chang develop romantic feelings for each other, finally.
Harry has a vision involving an attack upon Arthur Weasley (Mark Williams), from the point of view of Arthur’s attacker Nagini (the snake). Concerned that Voldemort will exploit his connection to Harry, Dumbledore tells Severus Snape (Alan Rickman) to give Harry Occlumency lessons which basically means Snape is supposed to drill in Harry’s mind and tells him to block him out of his mind, to defend his mind from Voldemort’s influence. The connection between Harry and Voldemort leads Harry to further pull back from his friends. Meanwhile, Bellatrix Lestrange (Helena Bonham Carter), Sirius’ deranged Death Eater cousin, escapes from Azkaban along with nine other Death Eaters, so bravo to the dementors. At Hogwarts, Umbridge and her Inquisitorial Squad expose Dumbledore’s Army. Umbridge becomes the new Headmistress and Harry’s relationship with Cho falls apart, as he thinks she snitched on Dumbledore’s Army.
Harry has another vision, this one of Sirius being tortured by Voldemort. Harry, Hermione, Ron, Luna, Neville, and Ginny fly to the Ministry of Magic on Thestrals in an attempt to save Sirius. The six enter the Department of Mysteries where they uncover a prophecy and Voldemort wanted that prophecy. However, they are ambushed by Death Eaters including Lucius Malfoy (Jason Isaacs) and Bellatrix Lestrange. Harry refuses to give Lucius the prophecy, and a fight between Dumbledore’s Army and the Death Eaters begins. The Death Eaters take everyone except Harry as hostages, threatening to kill them unless he surrenders the prophecy.
Harry obliges just as the Order arrives. As they attack the Death Eaters, Lucius drops the prophecy, destroying it. Just as Sirius overpowers Lucius, Bellatrix kills Sirius. Voldemort appears, but Dumbledore arrives through the Floo Network just before Voldemort can kill Harry because why not.
A duel between Voldemort and Dumbledore ensues, destroying much of the Atrium and Bellatrix escapes. Ministry officials arrive before Voldemort disapparates; Fudge is forced to admit that Voldemort has returned and resigns as Minister in disgrace. Umbridge is removed from Hogwarts and Dumbledore returns as headmaster.
