After some confusion in the spinning circular room, [Harry] finally manages to lead his friends into the [Hall of Prophecy]. There, [Ron] notices a circular globe with Harry's name on it, but when Harry picks it up, he soon hears [Lucius Malfoy]'s voice behind him, ordering him to hand it over.
Chatper 35 - "Beyond the Veil" - In which Lucius Malfoy, Bellatrix Lestrange, and other Death Eaters arrive and attempt to take the prophecy away from Harry. The D.A. members fight the Death Eaters and are separated. Hermione is hurt, Neville's nose is broken, and when they are reunited with the others, Ginny's ankle is broken and Ron is badly injured. Later, Luna is hurt. Remus, Sirius, Dumbledore, and other members of the Order of the Phoenix arrive to fight the Death Eaters. Sirius duels with Bellatrix and loses his life through the veil.
[Lucius Malfoy] and his [Death Eater] friends try to coax the [prophecy] out of [Harry]'s hands, but he refuses. Finally, the kids destroy shelves around them and make a run for it, getting just outside the room and sealing the door.
[Harry], [Hermione], and [Neville] realize they're alone and continue running from the [Death Eaters]. Before long one Death Eater's head gets caught in a jar of time, Hermione is knocked out, and Harry runs into [Luna], an injured [Ginny], and a silly [Ron]. When Ron further injures himself with a [brain], Harry leads the [Death Eaters] away, bouncing down the stairs. Neville follows but is caught, and to prevent him from getting tortured, Harry prepares to hand over the [prophecy].
Just before [Harry] gives up, the [Order of the Phoenix] bursts in to fight. In the ensuing melee, the [prophecy] shatters, [Dumbledore] arrives and begins to round up the [Death Eaters], and just as things begin to die down, [Bellatrix Lestrange] casts a spell that knocks [Sirius] through the [veil], gone forever.
Chapter 36 - "The Only One He Ever Feared" - In which Harry pursues Bellatrix and learns he is incapable of an Unforgivable Curse; Voldemort shows up; Dumbledore saves Harry from the Killing Curse; Fudge and other Ministry members witness Voldemort's return; and Dumbledore reinstates himself as Headmaster.
As the battle dies down around him, [Harry], enraged that [Bellatrix] has killed [Sirius], chases her through the [Department of Mysteries] and into the [Ministry of Magic]'s [atrium]. She demands the [prophecy], Harry tells her that it's smashed, and through his scar Harry realizes that [Voldemort] is enraged. Unexpectedly, he soon finds out why - because Voldemort is in the room.
[Voldemort] arrives and tries to kill [Harry], but is soon interrupted by [Dumbledore], and a duel for the ages ensues. Voldemort manages to possess Harry for a short time, but Dumbledore manages to drive him off, [Bellatrix] in tow, just as [Fudge] and a team of [Aurors] arrives.
With [Voldemort] gone, [Dumbledore] chastises [Fudge], finally forces him to listen to sense and stop babbling, and sends [Harry] back to [Hogwarts].
Chapter 37 - "The Lost Prophecy" - In which Harry has his final outburst in anguish over Sirius' death, and Dumbledore tells him everything - about why he must return to the Dursleys every year, about the prophecy, about how Voldemort marked him as his equal, about how it could as easily have been Neville, and about how either Harry or Voldemort must die. Dumbledore also admits to allowing his emotions to blur his judgement with Harry.