Summary of Order of the Phoenix

Harry is at the Dursleys for the summer. He becomes angry and frustrated that he doesn't hear anything about the activities of Lord Voldemort or of the wizarding world in general. After an argument with his aunt and uncle, Harry wanders around Little Whinging and spots his obnoxious cousin, Dudley. Dementors suddenly appear and attack, but Harry repels them with a Patronus Charm, although Dudley is severely affected by the encounter. When their neighbour, Mrs. Figg, arrives to help, Harry is astonished to learn she is actually a Squib, placed there by Professor Dumbledore to watch over him.

Vernon and Petunia blame Harry for Dudley's condition and demand that he leave. Harry receives an owl letter stating he has been expelled from Hogwarts for performing magic outside school. Several more letters arrive in quick succession: Arthur Weasley and Sirius Black warn Harry not to leave the house, while another overturns his expulsion and orders him to appear at a hearing at the Ministry of Magic. A Howler for Harry's aunt arrives from Dumbledore, who sternly warns her, "Remember my last, Petunia!" Visibly shaken, she tells Vernon that Harry has to stay.

Soon, Remus Lupin, Mad-Eye Moody and Nymphadora Tonks, among others, arrive to escort Harry to 12 Grimmauld Place, Sirius Black's home in London, which now serves as the secret headquarters for the Order of the Phoenix. There he is reunited with the Weasleys, Hermione, and Sirius, who is confined to the house while the Ministry still hunts him (see Harry Potter and the Prisoner of Azkaban). Harry is angry and argumentative with Ron and Hermione for withholding information about Voldemort, but they maintain that Dumbledore ordered them to absolute secrecy. Harry nonetheless manages to learn quite a bit about what has transpired but is unhappy to find out that both his friends have been made school Prefects while he has not.

Although both Harry and Dumbledore have sworn that Lord Voldemort has returned, few believe them. Indeed, the complacent Ministry of Magic, keen to avoid panic, have discredited them, using the wizarding newspaper The Daily Prophet to imply both Harry and Dumbledore are eccentric liars. Dumbledore's supporters, however, have revived the Order of the Phoenix to renew the battle against Voldemort.

Chapterwise Summary

Harry on Trial
The hearing for Harry's possible expulsion from Hogwarts finally arrives. The household is filled with trepidation, but everyone is confident Harry will be acquitted because underage wizards are permitted to use magic in self-defence. Arriving at the Ministry of Magic, Harry and Mr. Weasley discover that the hearing's time and location have been changed without their knowledge. They make it just in time, only to learn that the hearing is actually a trial with the entire Wizengamot assembled. This appears to be an attempt to intimidate Harry and to prevent Dumbledore coming to his defence, but the ancient wizard and headmaster of Hogwarts appears nonetheless. Mrs. Figg is also present and testifies that the Dementors were real and not figments of Harry's imagination or a lie. Harry is exonerated. Strangely, Dumbledore scarcely pays any attention to Harry and leaves without speaking to him. As Harry leaves the Ministry, he spots Lucius Malfoy conferring with Cornelius Fudge. Harry is shocked, as Malfoy is a suspected Death Eater, but Mr. Weasley alludes to bribery.

Return to Hogwarts
Harry and his companions return to school. On the Hogwarts Express they share a compartment with Ravenclaw student, Luna Lovegood, a rather odd girl whose father publishes The Quibbler, a quirky tabloid she claims prints important stories, although they appear to be unfounded sensationalist speculation. Back at Hogwarts, they discover Hagrid has not yet returned, and their new Defence Against the Dark Arts teacher is Dolores Umbridge, one of the panel members at Harry's Wizengamot hearing. Umbridge does not let students practice any magic in her classes, only allowing them to read the textbook. Appointed against Dumbledore's wishes, it is apparent she is there to spy on the school and impose the Ministry of Magic's agenda. In the meantime, the teachers are pushing hard to prepare Fifth-year students for the O.W.L. exams. Through a succession of Decrees passed by the Ministry of Magic, Professor Umbridge gains more influence at the school, culminating in her appointment as High Inquisitor. She begins intrusive and intimidating inspections of the teachers. In a letter to Ron, Percy Weasley, who now works for Cornelius Fudge, congratulates his younger brother on being made Prefect but advises him to 'sever ties' with Harry, who he says is an unbalanced, dangerous person to fraternise with. He also recommends Ron report anything unusual to Umbridge, "a very lovely, helpful woman." He hints this may be Dumbledore's final year at Hogwarts. Furious, Ron shreds and burns Percy's letter, choosing to remain loyal to Harry.

Umbridge's Oppression
It becomes apparent to the students that Umbridge is a particularly unpleasant character. Her lessons consist solely of reading the textbook with no practical training whatsoever. She states that there is no danger out there where the students would be compelled to use the practical applications to defend themselves, but the reality is that Minister Fudge fears that Dumbledore is secretly training a wizard army against the Ministry. In light of Umbridge's refusal to teach anything useful, Hermione convinces Harry to start secret lessons for students wanting to learn practical Defence Against the Dark Arts. He reluctantly agrees, and all the participants sign a paper swearing never to reveal the existence of the newly-named "Dumbledore's Army" to Umbridge. Hagrid finally returns, although he is badly bruised and battered. After some persuasion, he eventually divulges the details of his failed secret mission with Madam Maxine to recruit the giants to the Order's side to Harry, but he is reluctant to explain his injuries. Both he and Professor Sybill Trelawney are placed under heavy scrutiny by Umbridge, who views both incompetent and is prejudiced against "half-breeds" like Hagrid, who is half-human, half-giant. As Umbridge convinces Fudge to pass more edicts, activities in the school are severely curtailed. All student activities and organizations are banned until Umbridge reinstates them; the Slytherin Quidditch team is almost immediately reactivated, but the Gryffindor team is held up until Minerva McGonagall goes over Umbridge's head to Dumbledore. This eventually causes Dumbledore's own power as Headmaster to become secondary, in many respects, to Umbridge. Meanwhile, Ron becomes the new keeper for the Gryffindor Quidditch team. The Slytherins compose a taunting ditty entitled "Weasley is Our King" in an attempt to intimidate Ron into playing poorly. It succeeds, but Harry captures the Snitch in the first game to clinch victory. However, a fight provoked by Draco Malfoy results in Umbridge banning Harry and Fred and George Weasley from playing. Ginny Weasley replaces Harry as Seeker.

Dumbledore's Army
The Defence Against the Dark Arts classes, led by Harry, secretly continue. The students now call themselves the "D.A.", initially for Defence Association but that becomes Dumbledore's Army. The name expresses the students' defiance against the paranoid and complacent Minister of Magic, Cornelius Fudge and their loyalty to Dumbledore. Harry begins having strange dreams, mostly about running down a hallway and attempting to open a door in the Ministry of Magic's Department of Mysteries. Soon, however, Dumbledore places Harry under Severus Snape's tutelage to learn Occlumency, to prevent his thoughts from being penetrated. Eventually, their mutual animosity causes the training to be discontinued. However, during one session, Harry glimpses one of Snape's memories, revealing that Harry's father, James, and Sirius were school bullies who taunted Snape mercilessly. Hermione blackmails journalist Rita Skeeter into writing a story about Harry and Voldemort that refutes The Daily Prophet's barbs about Harry and exposes the truth about Voldemort's return. Furious, Umbridge bans the paper inside the school, but the story spreads quickly, gathering support for Harry and Dumbledore. Empowered by Ministry edicts, Umbridge sacks Professor Trelawney, but Dumbledore, citing his remaining authority as Headmaster, allows Trelawney to stay in residence at the castle. He also recruits a replacement Divination teacher, the centaur, Firenze. Umbridge dislikes what she refers to as "half-breeds," and is furious Dumbledore outwitted her with her own rules; an earlier Ministry Decree gave the Ministry power to make appointments when the Headmaster is unable to find a satisfactory candidate.

A Dating Disaster
Harry is attracted to pretty Ravenclaw Quidditch player Cho Chang, but he is awkward and shy around her. Her intense grief over Cedric Diggory's recent death makes him uncomfortable, although he is elated when they share a kiss under the Christmas mistletoe. During a Valentine's Day outing to Hogsmeade, their fragile relationship is further damaged when Cho becomes jealous over his friendship with Hermione. At first, Harry is amused over her misunderstanding and bursts out laughing, but this deeply offends Cho. Bursting into tears, she runs out of the teashop, much to Harry's embarrassment. Things unravel further after the DA meetings are exposed and Umbridge catches Harry. When he is taken to Dumbledore's office, he discovers that Cho's friend, Mariette Edgecombe is the informant. To protect the students, Dumbledore panders to Fudge's paranoia by telling him and Umbridge that he formed the DA to depose Fudge as Minister of Magic. Dumbledore spectacularly stuns the Ministry officials and is transported away by his pet phoenix, Fawkes, before he is able to be arrested. After his departure, Umbridge is appointed Headmistress. She quickly forms an Inquisitorial Squad, which bullies some of the students. The Weasley twins lead something of a revolt against the new Headmistress, creating mayhem throughout the school with their magical pranks while the Hogwarts teachers pointedly do nothing to help the new Headmistress. Both Harry and Cho defend their respective friends' actions, which leads to a heated argument. Seeing tears in Cho's eyes, Harry warns her that he won't tolerate her crying anymore. Stung, Cho storms off angrily, after which the two stop speaking, ending their relationship. Fred and George set off a decoy prank so Harry can sneak into Umbridge's office to talk to Sirius via the fireplace — the only one not under surveillance. The twins are caught, but they jump on their brooms and depart the school for good, leaving behind a magical swamp inside the school. As they depart, they announce the forthcoming opening of their own joke shop, 'Weasley's Wizard Wheezes', in Diagon Alley.

Sirius in Trouble
bleDuring the nighttime Astronomy O.W.L. exam, Harry witnesses unknown persons attempting to capture and expel Hagrid. Professor McGonagall attempts to intervene but is hit by Stunning Spells, incapacitating her and sending her to the hospital. During a later O.W.L. exam, Harry has a vision that Voldemort is torturing Sirius in the Department of Mysteries. Harry desperately attempts to contact Sirius via the fireplace in Umbridge's office, but the Black family's house-elf, Kreacher, tricks Harry into believing Sirius has vanished, when he is, in fact, tending to the Hippogriff Buckbeak. Umbridge and her minions — mainly Slytherin students — capture Harry and some of his friends. Unaware that Snape is an Order of the Phoenix member, Umbridge asks him for Veritaserum to use on Harry, but he claims he has none left. Harry uses Sirius' nickname ("Padfoot") to try and warn Snape that Sirius is in danger, but Snape seemingly ignores him and leaves. Umbridge tells Harry that it was she who ordered the Dementors to attack him during the summer and prepares to use an Unforgivable Curse on him. Thinking fast, Hermione concocts a story that Dumbledore has a powerful weapon hidden in the Forbidden Forest. She says that she and Harry will lead Umbridge to it.

Escape to London
Hermione, along with Harry, leads Umbridge to where she told her Dumbledore hid a "weapon" in the forest. There they encounter the haughty centaurs, who are furious that one of their brethren now works for humans. Hermione knows they are disposed to hate adult wizards, and when Umbridge foolishly insults them, they break her wand and carry her off screaming into the woods. The other centaurs are about to attack Harry and Hermione when Hagrid's half-brother - a "small" giant named Grawp that Hagrid has been hiding in the woods, suddenly appears, scattering the creatures. Ron, Ginny, Luna, and Neville arrive, having escaped their "Inquisitorial Squad" captors, and the group flies to the Ministry on the school's thestrals. Arriving at the Department of Mysteries, they find the room in Harry's dream. There is no sign of Sirius, but Harry sees rows of shelves containing glass balls, one of which has his and Voldemort's name on it, with the note "S.P.T. to A.P.W.B.D." (This is actually "Sibyll Patricia Trelawney to Albus Percival Wulfric Brian Dumbledore", as it was the former who made it and the latter who heard it). Death Eaters suddenly appear and demand the glass sphere. These include Lucius Malfoy, MacNair (the Ministry executioner of "dangerous beasts"), former Department of Mysteries employee Rookwood, and Bellatrix Lestrange, Sirius' cousin and one of the people convicted of torturing Neville Longbottom's parents into insanity. Harry discovers later that the glass orb contains a prophecy about himself and Voldemort. Voldemort knows only the beginning of the prophecy and he hopes the full contents will reveal the remainder. Only those who are the subject of a prophecy are able to take the sphere from its shelf without suffering insanity. It turns out that, unwilling to risk exposing his revived existence, Voldemort lured Harry to the Ministry to retrieve it for him. Realising there was a mental connection between himself and Harry, Voldemort implanted a false vision of Sirius being tortured, knowing Harry would try to rescue him.

The Battle at the Ministry
A fight erupts between the students and the Death Eaters. Most of the students are injured and nearly defeated. Tipped off by Snape, Order of the Phoenix members, including Sirius, arrive in time. During the ensuing battle, the prophecy sphere is shattered, against the Death Eaters' wishes. Tragically, Sirius is struck by a curse from his cousin, the Death Eater Bellatrix Lestrange. His body falls through a mysterious veiled archway and vanishes. Seeking revenge, Harry chases Bellatrix into the atrium, attempting to jinx her and even going as far as casting the Cruciatus Curse on her. Bellatrix blocks every spell except for the Cruciatus and demands the prophecy. Lord Voldemort apparates inside the atrium, and his terrible anger causes Harry's scar to hurt too intensely for him to be able to fight. However, Dumbledore suddenly appears and blocks a killing curse that Voldemort hurls at Harry. Voldemort and Dumbledore duel, and after a dramatic fight he possesses Harry's body and tries to goad Dumbledore into killing him, but the force of Harry's love makes the possession unbearable to Voldemort, who finally relents and disapparates with Bellatrix. Meanwhile, Ministry employees arrive in time to see Voldemort. Among them is Cornelius Fudge, who finally believes Voldemort has returned. In turn, The Daily Prophet reverses its hostile attitude towards the pair, restoring their reputations and praising them for warning the wizarding community of Voldemort's return.

The Prophecy
Safely back at Hogwarts, Dumbledore explains to Harry why he distanced himself from him during the year. He had sensed Voldemort's growing power over Harry—indeed, on more than one occasion, Harry was filled with a desire to strike down Dumbledore. Dumbledore also realised that Voldemort could learn about the Order of the Phoenix's plans through Harry, and deliberately concealed information from him. He tells Harry he regrets not teaching him Occlumency himself and underestimated Snape's deep-seated resentment towards his father, James. He also reveals the entire prophecy to Harry. When Dumbledore interviewed Sybill Trelawney for the Divination post sixteen years ago at the Hog's Head Inn in Hogsmeade, she unknowingly lapsed into a trance and prophesied that:
"The one with the power to vanquish the Dark Lord approaches...born to those who have thrice defied him, born as the seventh month dies...and the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not...and either must die at the hand of the other for neither can live while the other survives...the one with the power to vanquish the Dark Lord will be born as the seventh month dies..."
This was interpreted to mean that Voldemort would kill either Harry or Neville Longbottom who were both born at the end of July, or one of them would kill him. However, Voldemort only heard part of the prophecy, as his spy, who was eavesdropping on the conversation between Trelawney and Dumbledore, was thrown out before Trelawney completed the prediction. (The eavesdropper is later identified in Harry Potter and the Half-Blood Prince.) After Voldemort attacked baby Harry, the latter part of the prophecy was realised, and Harry, not Neville, became his foe and would kill or be killed by him. Had Voldemort heard the entire prophecy, he would have known that by attacking Harry he would transfer some of his own powers to him. Dumbledore remarks to Harry that this was Trelawney's first true prediction. The one in Harry Potter and the Prisoner of Azkaban was her second. Harry also learns why he must stay with the Dursleys each summer. When Harry's mother died protecting him, her sacrifice cast a protective spell on him that is sustained as long as he lives among his maternal blood relatives. Aunt Petunia, Lily's sister, therefore acts as Harry's protector, a role Dumbledore reminded her of when he sent her the howler. Dumbledore goes into the Forbidden Forest and retrieves Dolores Umbridge from the centaurs. She is confined to the hospital wing in a severely traumatised state, although she is expected to recover.
Harry returns to the Dursleys', but not without Vernon and Petunia receiving a stern warning from a menacing Alastor Moody to treat Harry better. Changes are brewing in the wizarding world. Indeed, the last chapter of the book is entitled "The Second War Begins."

Notes
The Death Eaters captured at the Ministry were: Lucius Malfoy, Nott, Jugson, Rodolphus Lestrange, Antonin Dolohov, Crabbe, Rabastan Lestrange, Walden Macnair, Avery, Augustus Rookwood, and Mulciber. Lord Voldemort and Bellatrix Lestrange were also at the Ministry, but they escaped. This list includes most of the Death Eaters whose names were known to the reader at this time, though Peter Pettigrew and Goyle were both absent from this mission and likely others as well, given the number of Death Eaters that Harry saw at Voldemort's rebirth in Harry Potter and the Goblet of Fire.