[Neville] greets [Harry], [Ron], and [Hermione], and Harry notices that he looks beat up, like an old man. He soon helps them through the tunnel, though, and on the way tells them about the changes at [Hogwarts]. The [Carrows] have been torturing students and coming after [D.A.] members, forcing them to go into hiding.
Emerging into the [Room of Requirement], [Harry], [Ron], and [Hermione] are greeted enthusiastically by their friends. The room turns silent when the trio tries to go off alone again, but as dozens more friends arrive, Ron and Hermione realize they can ask the others for help - and they do. Finally, as [Voldemort] continues to discover his lost [Horcruxes], the [Ravenclaws] point Harry toward the lost [diadem], and the statue in the [Ravenclaw common room].
With the help of the [Marauder's Map], [Harry] and [Luna] make their way to the [Ravenclaw common room], and thankfully Luna manages to answer the question correctly on the first try.
In the [Ravenclaw common room], [Harry] gets a look at [Ravenclaw's diadem], but also at [Alecto Carrow], who was waiting for him, and calls [Voldemort] almost before Harry realizes what's happening.
As [Harry]'s mind swims into [Voldemort]'s, [Luna] [Stuns] [Alecto Carrow], setting off a bang loud enough to attract all of [Ravenclaw]. Soon [Amycus] arrives at the door, along with [McGonagall], and when they see Alecto on the floor, they begin arguing over who to blame. When Amycus spits in McGonagall's face, though, Harry reveals himself, [Crucios] Amycus, and tells McGonagall of his search for the school, as she agrees to put up defenses.
[Harry], [Luna], and [McGonagall] race through the corridors of [Hogwarts] until they run into [Snape], who McGonagall promptly attacks. As they duel, [Flitwick], [Sprout], and [Slughorn] arrive and help her drive Snape off, and he flies away.
As the professors begin to set up defenses and gather their students (and [McGonagall] challenges [Slughorn to step up and fight in the name of [Slytherin House]), [Harry] and [Luna] rush back to bring everyone from the [Room of Requirement] to the [Great Hall].
Back in the [Room of Requirement], [Harry] announces to the still-swelling crowd that [Voldemort] is coming and the castle is preparing to fight. A huge cheer erupts, then, as the crowd makes its way out the door to the [Great Hall].
With most of the crowd gone, the [Weasleys] remain behind, with [Molly] determined not to allow [Ginny] to fight. As they argue, [Percy] shows up, apologizing to his family, and they all settle on Ginny staying in the [Room of Requirement] to keep watch. Finally [Harry] prepares to leave, and as he does, he sees another vision of [Voldemort] - at the gates of [Hogwarts].
In the [Great Hall] [McGonagall] announces the evacuation orders, but is interrupted by [Voldemort]'s voice asking for [Harry Potter] to be handed over, with a deadline of midnight. [Pansy Parkinson] tries to apprehend him, but is stopped by the rest of [Hogwarts], and is the first one led out the door to be evacuated, with much of the school in tow.