Harry, Ron, and Hermione appear in Hogsmeade, but their appearance triggers a magical alarm that sounds like loud screaming. A dozen Death Eaters burst out of the Three Broomsticks pub in search of them. Though they remain under the Invisibility Cloak, they have nowhere to hide, and they infer from the Death Eaters’ comments that enchantments will keep them from teleporting away again. The Death Eaters unleash dementors in search of them, and Harry summons his Patronus, potentially giving their position away.
Before the Death Eaters can find them, however, a door opens in a house on the street, and a rough voice summons them inside and into a room above the Hog’s Head Inn. Still cloaked, they look out the window down at the street below, where the man who saved them—whom Harry recognizes as the Hog’s Head barman—argues with the Death Eaters. The man claims that it was he who set off the alarm, letting his cat out after curfew. He claims that the Patronus was his own goat Patronus, not Harry’s stag, and points out that Voldemort won’t want to be summoned over a cat. Mindful that the Hog’s Head bar is a convenient place for them to trade black market goods, the Death Eaters leave him alone.
Harry recognizes the man’s blue eyes as those he’s been seeing through the magic mirror, and he realizes that this man must be Aberforth, Dumbledore’s brother, and that Aberforth was the one who sent Dobby. Aberforth acknowledges that he’s been trying to keep an eye on Harry, though it was not he who led them to the sword.
Aberforth tries to convince Harry that Voldemort has already won, and that Harry should abandon his quest—whatever it is—and leave the country, before he meets Dumbledore’s fate. He reminds them of his brother Dumbledore’s penchant for lies and secrecy, and says that many of those Dumbledore loved and cared for turned out to be worse off than if he’d left them alone.
Hermione guesses that Aberforth is talking about his sister, Ariana, and prods him into giving them the real story of what happened to her. Ariana was not a Squib, as Rita Skeeter claimed. When she was six years old, as her magic was beginning to manifest itself but before she could control it, she was observed doing magic by three much older Muggle boys, who attacked her in some unspecified way, leaving her permanently unhinged. Dumbledore’s father was imprisoned in Azkaban for attacking these boys, and Dumbledore’s early flirtation with the idea of wizards dominating Muggles stemmed from anger at what had happened to his sister and father, coupled with a wish to create a world in which his sister would not have to hide.
Dumbledore returned home when his mother, Kendra, died and took responsibility for Ariana. He met Grindelwald, and the two began hatching grand plans to change the world, wanting to set off as soon as possible. Aberforth confronted them, pointing out that Ariana was in no fit state to travel or be left alone, so they had no way to do whatever it was they wanted to do. As the argument grew heated, Aberforth drew his wand, and Grindelwald used the Cruciatus (torturing) curse on him. As the three fought, Ariana came to intervene, and one of the curses the three wizards were hurling at each other killed her. Grindelwald left immediately, and Dumbledore was free to embark on his career.
Harry tells Aberforth that Dumbledore was never free of his past, and describes how Dumbledore, when he drank a potion and went out of his mind in the previous book, was begging an unseen figure to hurt him instead of “them”—clearly a memory of seeing Grindelwald hurting Aberforth and Ariana. Harry says that he hasn’t given up on the Order of the Phoenix and intends to defeat Voldemort, and Aberforth agrees to help him get into Hogwarts.
Aberforth turns to an oil painting of Ariana on the wall and tells the picture of Ariana that she knows what to do. Ariana turns around within the picture and walks down a tunnel, growing smaller and smaller until she disappears, eventually returning through the picture with a bedraggled and scarred Neville Longbottom, who emerges from the painting into the room.
Neville wants to know if rumors he’s heard about Harry breaking into Gringotts are true, and Harry confirms this. Neville describes what’s happening at Hogwarts: the Carrow siblings, Amycus and Alecto, have been made professors and put in charge of discipline. Amycus teaches students how to use the Cruciatus Curse, while Alecto teaches Muggle studies with an anti-Muggle bias.
Neville proudly shows the scars he earned for standing up to the Carrows. Neville remembered that when Harry stood up to unjust authority figures, it gave the rest of the students hope, so he tried to fill this role after Harry left school. Luna was taken away from school, and Ginny never returned after Easter break, so Neville found himself increasingly on his own in carrying out underground acts of resistance against the new regime. Eventually, the Death Eaters tried to stop Neville by going after his grandmother, who put a Death Eater in the hospital and then went on the run. Neville knew that it was time for him to disappear, and he has been in hiding in the Room of Requirement, which they had used in Harry Potter and the Order of the Phoenix.
Neville leads Harry and company through the portrait into the Room of Requirement. About twenty students are hiding in it, all members of Dumbledore’s Army and supporters of Harry who’ve been driven into hiding. They are wild with joy at seeing Harry and his friends. Soon after, Luna Lovegood and Dean arrive. All of the students are eager to help Harry, and are unhappy and resentful to hear that Harry, Ron, and Hermione are on a mission alone that they won’t disclose or accept help with. With some prodding from Ron and Hermione, Harry realizes that he doesn’t have to be quite as cryptic as Dumbledore and can recruit help in searching for the Horcrux without explaining what it is.
Harry tells the assembled students that they’re looking for a distinctive object, and that they don’t know what it is but think it might be associated with Ravenclaw (given that other objects were associated with other houses). Luna volunteers that there is a legend about a lost diadem of Ravenclaw, which has been gone for centuries. Harry could see a reproduction of it on the statue of Rowena Ravenclaw in the Ravenclaw common room.
Luna and Harry put on the Invisibility Cloak, and Luna leads him to the room so he can see it. Instead of a password, the Ravenclaw door is opened by answering a very philosophical question. The knocker asks, “Which came first, the phoenix or the flame?” and Luna opens the door by answering, “A circle has no beginning.”
Harry climbs up on the statue to get a good look at the tiara, but is apprehended by Alecto Carrow, who touches her Dark Mark to summon Voldemort.
Aberforth’s story gives Harry a better perspective on the story of Dumbledore’s youthful mistakes, providing the essential details—that Ariana was not a Squib but was attacked by Muggles—that make Dumbledore, his mother Kendra, and even his father all seem human rather than monstrous. So complete is Harry’s shift in attitude toward Dumbledore that he is now in a position to defend Dumbledore to Aberforth. Harry’s resolve to complete Dumbledore’s mission is intact, and it is enough to galvanize others who have given up. In the last chapters of the novel we see Harry as a leader, and we see Harry’s leadership reflected in others.
Neville’s newfound heroism is a pleasurable reversal of his role throughout the series as the most timid and least competent student in Harry’s class. As Neville explains it, however, his own heroism is not simply a matter of difficult and challenging times bringing out the best in his own character. Instead, Neville modeled his heroism and leadership after Harry’s. When Harry did not appear in school, Neville stepped in to fill the role. As the intimidated whipping boy of the school for so long, Neville was well able to appreciate the importance of those who take a stand and show leadership.
Neville’s adoption of Harry’s role and his continuation of Harry’s struggle demonstrate an important way in which human beings can connect with one another even after losing one another. A central problem of the book, expressed vividly in the epigraph from Aeschylus, is how we can be connected to people we have lost. Important people have died, and Harry has felt—particularly in the graveyard in Godric’s Hollow—that they are simply gone, unable to care about him or his struggles anymore. But Neville’s actions show Harry that there is a way to stay connected to people who have left us, if we keep faith with them and continue their struggle.