View of the sky, clouds mostly in dark greys or black, highlighted with silver whenever ominious thunder rumbles. In the background, a voice singsongs, "I killed Sirius Black!", laughing and gloating.
Harry (Daniel Radcliffe) appears, as he did near the end of "Harry Potter and the Order of the Phoenix". He is emerging from the fight with Voldemort in the Ministry of Magic, shards of glass in his face and cuts. Flashes are shimmering off the boy wizard, and we see several reporters and their camera crew trying to ask questions and take photos. Dumbledore (Michael Gambon), standing next to Harry, puts an arm around the boy and squeezes his shoulder to reassure him as they walk through the press melee. The scene briefly flashes back to the clouded sky, and the title appears.
The sky then appears as a reflection in a high-rise building in London, and the camera climbs to the heights of an office building. Several employees stop their work to move towards the window, gaping as the clouds gather to form a skull with a snake uncoiling from the jaw, and then several black trails screech through roads and alleyways, passing several tourist spots on the way. The trails reach Diagon Alley and explode into Ollivander's Wand shop, and one Deatheater, Fenrir Greyback (Dave Legeno) comes out of the shop holding a man with a sack over his head. Several more explosions occur, and the Deatheaters turn into black smoke again, heading towards the Millennium Bridge with several Muggle pedestrians. The Deatheaters become invisible as they reach the bridge, and zoom quickly over and around the bridge. The cables twist and turn, and the Muggles run screaming, before the bridge snaps and falls into the Thames (river).
The scene then changes to the Underground, where trains are zipping on their regular routes, and moves into a cafe where Harry is sitting with a copy of the Daily Prophet, reading about Lucius Malfoy's trial in the Wizengamot. A very pretty waitress comes up to Harry and asks whether he's Harry Potter. "I'm a bit of a tosser, really," he replies, self-conscious. He then starts to ask something, but the girl smiles and says, "Eleven. That's when I get off." Harry grins, checks his breath, and swallows some mints before looking out the window across the platform. Dumbledore is standing there, looking back at Harry.
Harry goes across, and notices Dumbledore's blackened right hand. "It's a most interesting story, if I do say so myself," Dumbledore teases. He then chides Harry for being reckless this summer, but he then requests Harry to come with him. Harry briefly looks back at the waitress, who has come out of the cafe and is looking up and down the platform, but he places his hand on Dumbledore's left arm. The pair suddenly apparate to Budleigh Babberton, a very dark and quiet village. Dumbledore compliments Harry on how well he went through the Apparation, and quips, "Most people vomit the first time." "I can't imagine why," Harry quips back, unsteady on his feet but following the headmaster's lead to an imposing mansion. They both draw their wands, and as they enter the house, they see much wreckage and blood dripping from a ceiling. Dumbledore tastes the blood, and a look crosses his face before he turns and pokes a striped armchair with his wand.
"Merlin's beard!" A man's head comes up from the back of the chair, and the chair seems to stand as it transforms into Horace Slughorn (Jim Broadbent). Slughorn has been on the run from Deatheaters for some time now, never staying more than a short time in any place. Dumbledore repairs the house, and Slughorn begins to bluster that he won't do what Dumbledore wants. Dumbledore calmly asks if he can use the loo, and goes off, leaving Harry with the former professor. Slughorn shows Harry his collection of photos of his favorite students, including Lily Evans, Harry's mother. He also points out a boy called Regulus Black. "I taught all the Black family... all except Sirius," he sighs. He mentions that he heard that Sirius had died recently, and then murmurs that he "would have liked the set."
Dumbledore returns, brandishing a woman's magazine and asking if he can keep it for the knitting pattern, then makes his farewells. Slughorn is confused, but Harry follows Dumbledore out, and finally Slughorn whinges that he'll come back to Hogwarts but only if he can have Professor Merryweather's old office and a pay rise. "These are mad times, mad," Slughorn moans. "They are indeed," Dumbledore murmurs. He then congratulates Harry, who being both famous and talented was the nudge Slughorn needed to change his mind, as Slughorn likes to "collect" talented students. Dumbledore then apologizes about taking Harry from the waitress: "She was truthfully very pretty." Harry figures he can try again the next night, but Dumbledore says Harry is going someplace else.
At the Weasley house in Surrey, Ginny Weasley (Bonnie Wright) notices that Hedwig and Harry's school trunk have appeared in the family kitchen. She asks her mum, Molly (Julie Walters) when did Harry arrive. Ron (Rupert Grint) pokes his head out and says he'd know if his best friend were there, and Hermione (Emma Watson) also emerges, asking about Harry. Ginny finds Harry first, who had found himself alone, outside the house and standing in a shallow stream. They hug, but are awkward as she leans back. Hermione and Ron rush up next, and Harry tells Mrs Weasley that Dumbledore brought him. A bit later, Harry is in a room with Ron and Hermione, while a ball of newspaper is burning in midair between them. Ron admits that his mum had doubts about sending him and Ginny to Hogwarts in September, and Hermione confesses that even her parents have noticed that things are not entirely safe there. The thought is that Dumbledore is getting old. Harry bursts out against this, but then stammers, "How old is he?" "Going on a hundred and fifty, I reckon," Ron says. The friends break up into laughter, as the flames begin to burn through a photo of Draco (Tom Felton) with his mother coming out from Lucius's court appearance.
In another part of England, two dark cloaked women are walking hurriedly through a torrential rain. One is Bellatrix Lestrange (Helena Bonham Carter), the other Narcissa Malfoy (Helen McCrory). They reach a terraced house and knock; Wormtail (Timothy Spall) answers and brings them to Severus Snape (Alan Rickman) in his study. Snape orders Wormtail out, using magic to force him, and Narcissa begins to plead with Snape about the task which the Dark Lord has set for Draco. Bellatrix chides her not to tell, and Snape reveals that he already knows what it is. Narcissa hopes that Snape might find a way to remove the task from Draco, and although Snape explains that he cannot change Voldemort's decision, he can protect young Malfoy. Bellatrix wonders whether Snape would take the Unbreakable Vow, and is astonished when he agrees.
Back in Diagon Alley, Harry, Ron, Hermione and Ginny are visiting Fred (James Phelps) and George's (Oliver Phelps) joke shop, which is doing huge business while the rest of Diagon Alley is practically deserted. Fred and George sell Harry some Peruvian Instant Darkness Powder, and the three heroes walk towards the shell of Ollivander's. While there, Ron notices Draco and his mum hurrying along towards Knockturn Alley. The trio follow, and while Draco pauses briefly at the door of Borgin & Burke's, he goes in regardless. Harry and his friends climb onto a roof, and try to see what's going on, as Bellatrix and Fenrir also enter for some gathering. Fenrir almost spots the kids, and after that, blinds descend all over the shop. Later, while heading on the Hogwart's Express to school, Harry theorizes that they saw some kind of ceremony to initiate Draco as a Deatheater, but neither Ron or Hermione are persuaded. Harry gets up and walks down the corridors towards the Slytherin section, and puts on his invisibility cloak after using the Peruvian Instant Darkness Powder to enter and hide himself so he can try to eavesdrop.
Draco tells Pansy Parkinson (Scarlet Byrne) and Blaise Zabini (Louis Cordice) that he doesn't see himself spending next year in Charms class, and says he'd throw himself off the Astronomy tower if he thought he was going to be there much longer. But he also looks up at the luggage rack above him, and when the train arrives, he tells his friends to get off without him. He then uses the Petrificus Totallis spell on Harry, pulls off the invisibility cloak and kicks Harry a few times before goading him, "Enjoy the train trip back to London." Fortunately for Harry, Luna Lovegood (Evanna Lynch) is walking up and down the corridors while wearing SpectreSpecs, and despite his cloak, she sees him. Harry then walks with her to the castle, apologizing that she missed the carriages. "That's okay, it was like walking with a friend," she smiles, and they see Professor Flitwick (Warwick Davis) waiting at the gate for them. Filch (David Bradley) is going through Draco's things as they walk up, and but Snape vouches for Draco. When Harry enters the Great Hall, Ginny looks up and says, "He's covered in blood. Why is he always covered in blood?"
Dumbledore stands and introduces Slughorn as the new professor for Potions, and then announces that Snape has been made teacher for Defense Against the Dark Arts, to the applause of the Slytherins. Dumbledore talks about why all the precautions have been taken, but then adds that for the forces of evil, "their greatest weapon is you." Draco hardly seems to be listening, resting his chin on one hand, but he looks more disturbed than malicious.
On the next morning, Professor McGonagal (Maggie Smith) is trying to guide the new students towards classrooms, and asks Harry why he hasn't gone to Potions. He explains that since Snape only accepted students with Outstanding on their OWL exams, he didn't think he could take it. McGonagal points out that Slughorn is willing to take students with Exceeds Expectations for an OWL level, and tells him to take Weasley too, as Ron looks "far too happy" for McGonagal's liking. When the boys arrive at the class, Slughorn tells them to take a textbook each from the cupboard. One book looks new, the other has a frayed and stained cover. Ron manages to wrestle the new copy away from Harry, and Slughorn tells the students about the potions he has prepared already. One, a particularly strong love potion, seems to pull quite a few girls in the class to it until Slughorn puts the lid on the cauldron. He then shows then a vial of Felix Felicis, which is also known as Liquid Luck, and he promises to give the vial to any student who can produce a high enough quality cauldron of the Draught of Living Death. Harry opens the frayed copy of the book, and sees "Property of the Half-Blood Prince", and as the class starts to work, he sees handwritten notes giving advice counter to the textbook's. But the notes help Harry to produce the quality potion, and Slughorn cheerily hands over the vial of Felix.
Later, Harry enters Dumbledore's office, and the headmaster shows him a case filled with several vials all containing memories relating to Voldemort. Dumbledore shows Harry a vial that holds the first time the headmaster personally encountered Tom Riddle, when he was living in an orphanage. Young Riddle (Hero Fiennes-Tiffin) thinks Dumbledore is a doctor, there to put him into a mental institution, but Dumbledore says that Hogwart's is not a place for mad people, it's a school. However, when Riddle demands that Dumbledore prove what he's saying, Dumbledore creates the image of the wardrobe being on fire, and forces Riddle to bring out the objects he took from other orphans. "Thievery is not tolerated at Hogwart's," Dumbledore reprimands, and before he leaves, Riddle says he can talk to snakes. "Is that normal for someone like me?" The memory ends there, and as Harry emerges from the pensieve he viewed it in, Harry asks about Slughorn. Dumbledore agrees that Slughorn has a very important memory as well. Harry states that Slughorn "collects" students, and that he would like to add Harry to that group. "Do you want me to let him?" Harry asks. Dumbledore nods.
While some Deatheaters try to fly to Hogwarts but hit a forcefield and are repelled, Draco goes through an empty hall, and finds the Room of Requirement. In there, he uncovers a cabinet exactly like one in Borgin & Burke's.
Later, Harry is trying to form a new Quidditch team for Gryffindor. Ginny has to shout, "SHUT IT!" to get the attention of everyone, and Harry explains that he wants to see everyone try out. A handsome boy comes up to Ron and introduces himself as Cormac McLaggen (Freddie Stroma). He's trying out to be Keeper. Ron stammers that Cormac has the build of a Beater: "Seekers need to be light, quick--" Cormac, however, catches a fly mid-flight, and grins, "I fancy my chances." He then looks up to where Hermione is sitting, and he asks to be introduced. "I wouldn't mind being on first name terms with Granger." Another girl, Lavender Brown (Jessie Cave), is watching Ron's performance as closely as Hermione is, but it's Hermione who uses the Confundus Charm to prevent Cormac from blocking the last goal. While Ron is congratulating himself on making the team again, Hermione starts to wonder about Harry's Potions book, but Ginny is the one who pulls it away and sees "Property of the Half-Blood Prince".
When the three head into Hogsmeade, they spot Ginny with her boyfriend Dean Thomas (Alfie Enoch). Ron is disgusted, and says they should leave. Hermione, who drinks a lot of her Butterbeer quickly, turns the tables on him: "If you and I were snogging, and Ginny came in, should she leave?" Ron is then blinking and flustered by the idea of snogging Hermione (kissing very passionately). But Harry, while distracted by Ginny, notices Draco acting suspiciously. Later, as they leave the pub, a girl rushes up to them, and Katie Bell (Georgina Leonidas) is flat on the snow. Suddenly some magical force pulls her several feet off the ground, arms outstretched, apparently screaming with no sound. Katie falls back to the ground, and as she twitches and shake, Hagrid (Robbie Coltrane) hurries up. He instructs Harry to only touch the object on the ground by its wrapping.
Professors McGonagal and Snape are looking at the necklace that Katie had accidentally touched, and her friend says Katie claimed she had to take it to Dumbledore. Snape notes that Katie is lucky to be alive, due to the curse that had been laid on the necklace, but when Harry claims Malfoy is responsible although he has no proof, Snape sneers, "How grand it must be, to be the Chosen One."
Professor Slughorn is holding a dinner for his potential Slug Club of talented students. Harry and Hermione are there, as is Neville (Matthew Long), Cormac, Blaise Zabini, and a boy named Marcus Belby (Robert Knox), who is gorging himself on profiteroles. Ginny comes in at this point, her eyes red, and Hermione whispers to Harry that Ginny must have been fighting again with Dean. Harry stands as Ginny comes to the table, while Cormac tries to flirt with Hermione. Ron, dressed for a Quidditch game with Slytherin, listens to their stories, but only gets interested when Hermione says she was thinking of taking Ron as her date to Slughorn's Christmas party. But his nerves about the game override this momentary pleasure, and even when Lavendar praises Ron about how he'll do, he threatens to resign when the game is over. Harry pushes a cup towards Ron, and Luna (wearing a beautiful lion's head mascot costume) asks what Harry put in the juice. Harry briefly shows the vial of Liquid Luck, and Hermione says Ron mustn't drink it. Ron, however, chugs the lot, and a confident grin spreads across his face. "C'mon, Harry. We've got a game to win."
In the game, Ron makes some spectacular saves, living up to the Liquid Luck reputation of being able to do no wrong while it's taking effect, and in the Gryffindor Common Room, Hermione blasts Harry for "cheating." He counters that the Confundus Charm was hardly playing fair, but then shows Hermione that all he did was fake putting the Liquid Luck into Ron's juice. Unfortunately for Hermione, at this point, Lavendar grabs Ron by the shirt front and starts tasting his tonsils enthusiastically. Hermione leaves the room, and Harry follows her. A group of birds are chirping over her head when he finds her ("just practicing," she says), but she's crying too. Ron and Lavendar, running along hand in hand, happen upon them, and Hermione sets the birds at Ron. The Weasley lothario leaves, and Hermione crumples into Harry's arms as they both think about the people they really fancy. The camera moves around the tower from Hermione crying in Harry's arms, to Ron and Lavendar necking, to Draco at the top of the Astronomy tower.
Later, Hermione chastises Harry about girls like Romilda Vane (Anna Shafer) trying to slip him a love potion purely because he's thought to be "the Chosen One", and then says that given the circumstances she won't be taking Ron as her date to the Slughorn Christmas party. Harry says that, since neither he nor Hermione can actually go with the people they like, he'd hoped to go with her as friends. Hermione gasps, because she should have thought of that, but has already made plans which she won't tell him about. Harry decides he'll find someone "cool".
He brings Luna, wearing a silver dress that looks like a lampshade. Neville is working as a waiter, having failed to make the grade in Slughorn's estimation, as had Marcus. Draco, meanwhile, has gone to the Room of Requirement again, and puts an apple in the cabinet. He says an incantation, and the apple is gone when he opens the door. He says another incantation, and the apple comes back, although it has had a bite taken out since it disappeared. Draco then tries and manages to sneak into the room where the Slughorn Christmas party is going on. Hermione had gone to the party with Cormac, although she is now trying to avoid him. Snape arrives in time for Cormac to vomit on his shoes, and Snape relays a message to Harry that Dumbledore is travelling and will only be back after the term begins again. At this point, Mr Filch finds Draco, and Snape removes the Slytherin boy from the party. Harry follows, and overhears Snape's remark about the Unbreakable Vow. Draco also rants about how he was Chosen for this task: "This is MY moment."
As Harry and Ron are on the train heading to the Burrows for Christmas with the Weasley family, Ron admits to Harry that if the terms of an Unbreakable Vow aren't met, the person who takes it will die. Harry asks both Remus Lupin (David Thewlis) and Arthur Weasley (Mark Williams) for their opinion of Snape and Draco's confrontation. Remus is afraid that doubting Snape reflects doubt on Dumbledore, as Dumbledore trusts Snape. Mr Weasley, however, has information about the cabinet Harry described seeing at Borgin & Burke's: it's a Vanishing Cabinet. When Voldemort was at the height of his powers before, many people used such cabinets to hide from Deatheaters. But then Ginny comes in with a small plate of mince pies, and Mr Weasley leaves the room. Ginny says, "Open up, you. Don't you trust me?" and puts a pie in his mouth. But before they can do much else, Ron comes in with a huge plate loaded with mince pies. He sits down between his sister and best friend, looks at both of them and says, "Pie?"
Remus and Tonks (Natalia Tena), who are a couple now, are about to leave the Burrows when Remus seems to sense something unusual. Upstairs, Harry and Ginny see a fireball racing towards the house. It becomes Bellatrix, who begins her singsong chant again, "I killed Sirius Black!" A circle of flame surrounds the house, except for a small break that Bellatrix jumps through. Harry manages to race through before the space closes, and it takes the combined efforts of Remus, Tonks and Mr Weasley before another break opens that's wide enough for Ginny to run through, too. Remus and Tonks also follow, racing through the shafts of wheat that are clustered thickly in the fields all about the Burrows, and Ginny finds herself facing Fenrir. Harry leaps in front of her to try to keep her safe, and Bellatrix joins Fenrir. Remus and Tonks also find the group, so the Deatheaters fly away as black smoke. But they manage to shoot enough fire at the Burrows to engulf the house in flames, and all the Weasleys are standing with Harry, Remus and Tonks as the Weasley family home burns.
The next scene is another memory. In it, Professor Slughorn is talking with a group of students including a 16 year old Tom Riddle (Frank Dillane). Riddle is coaxing Slughorn to share information about something he read from the Restricted Section of the Library. Slughorn grows defensive, in spite of previously glowing under Tom's gentle praise, and shouts, "Get out of here at once." Harry comes out of the memory, and Dumbledore tells him that it has been tampered with by Slughorn. However, he needs Harry to get the real memory from the Potions Master. Harry tries, but Slughorn recognizes that Dumbledore is behind it all and he won't talk.
Harry goes back to his room, only to find Ron staring vacantly at the moon, having eaten the chocolates that had been on Harry's bed. Ron "loves her," but when Harry mentions Lavendar, Ron is indignant. He's in love with Romilda Vane. "You don't even know her!" Harry says. "That's true," Ron remembers. "You could introduce us!" He then settles back to staring at the moon, until Harry pulls him up and takes him to Professor Slughorn. Slughorn wonders why Harry, who's such an ace at potions, didn't whip up an antidote himself. Harry points out that this needs a practiced hand, as Ron starts to cuddle the professor. A couple of seconds after Ron swallows the antidote, he asks what happened. Slughorn decides they all need something "restorative", and pours out three glasses of oak-matured mead. Ron sips his mead first, but before the others can even taste theirs, Ron falls to the floor, foaming at the mouth while his skin goes waxy. Harry rushes to the boxes of Slughorn's herbs and finds a bezoar, which he forces Ron to swallow. Ron finally coughs and sits up, muttering, "These girls, they're gonna kill me."
Ron is taken to the hospital wing, and Dumbledore, Snape and McGonagal join Hermione and Ginny in the crowd around Ron's bed. He's now lying unconscious, very pale, and the teachers try to figure out where the mead came from. Lavendar hurries in, gasping, "Where is he? Where's my Won-Won?" but when she sees Hermione, her eyes narrow. "What's she doing here? I'm his girlfriend!" "I'm his... friend," Hermione says, fumbling, but everyone goes quiet as Ron starts to try to say something. "Her...my...own...ee," he hisses. Lavendar is incandescent, but Hermione sits on the bed and takes Ron's hand, smiling softly. Dumbledore gently asks everyone else to leave, and Ginny says, "About time."
Harry follows Draco towards the Room of Requirement again, and Draco puts a bird in the cabinet. This time, though, the bird is dead when it returns from the journey. The Slytherin boy cries, looking frustrated.
While Ron wonders how he broke up with Lavendar, admitting he remembers nothing from that night in the hospital wing, Harry sees Katie Bell come in. She's finally recovered from the curse, but she has no memory of how she got the cursed necklace. But Draco looks white with guilt when Katie comes in, and Harry follows him to a bathroom. Draco washes his face but begins sobbing, until he sees Harry. Both boys begin trying to hex each other, and Harry finally uses the Sectumsempra curse he found in the Half-Blood Prince's potion book. But it makes several deep bleeding wounds across Draco's chest and stomach, and Snape races in, managing to reverse the worst of the damage before Draco dies. Harry is sick with guilt, and Ginny, Ron and Hermione tell him that he's got to get rid of the book. She leads Harry to the Room of Requirement, and once in there, she has him close his eyes so he can't see where she hides it. She then takes advantage of him standing there by kissing him. Harry is then startled when Ron asks, "Did you and Ginny do it? Hide the book." Ron then sees Slughorn walk away from them, and mutters, "No luck with Slughorn, then."
This reminds Harry of the Felix Felicis. He swallows the contents, and then when Hermione starts outlining Slughorn's usual schedule, Harry replies he's going to Hagrid's. "I just have a really good feeling." On his way, he sees Slughorn trying to clip a few leaves off plants in Professor Sprout's greenhouse. (The leaves are quite valuable). Slughorn says it's nearly dark, that he can't let Harry walk outside the castle on his own. Harry says, "Come with me then." He manages to get Slughorn to where Hagrid is standing by the body of Aragog, the enormous spider Hagrid raised a long time ago. Slughorn knows that the venom is also very precious, and milks the dead spider's fangs before saying a few words over the body. Hagrid and Slughorn then both get plastered over a lot of drink in Hagrid's hut, while Harry watches, grinning and waiting. When Hagrid slips into unconsciousness, Harry talks about how his mother died to protect him. "Be brave, professor. Be brave like my mother. Otherwise, you disgrace her memory." Slughorn, near tears, begs Harry to not think badly of him when Harry sees the true memory.
The true memory clearly reveals that Riddle was asking about horcruxes, and that by putting a piece of one's soul in an object, even if one's body was attacked and killed, a person would not die. Riddle asks how a soul can be split, and whether seven, being an important magical number, might be more desirable than just one. Harry emerges from the memory, and realizes that this is what Voldemort did. Dumbledore shows Harry Tom Riddle's old diary (from "Chamber of Secrets") and a ring that Riddle had been wearing in the memory, and says he will need Harry's help to destroy the next one he knows of.
Harry finds Snape and Dumbledore at the top of the Astronomy Tower, where Snape is asking why Dumbledore expects too much of him. "I do not want to do this." Dumbledore stresses that Snape promised, and dismisses him. He then says that Harry can only come with him if Harry promises to obey Dumbledore, even if Harry is ordered to save himself and leave Dumbledore to the worst. Harry gives his word, and Dumbledore holds up his arm. Harry is surprised: "Sir, I thought you couldn't apparate within Hogwarts?" "Well, being me has its privileges."
They find themselves on a pointed rock in the ocean, outside tall cliffs. A large crack in the cliffs is their next destination, and Dumbledore uses a cut in his hand to gain entry. He then sends out a light from his wand to locate where they need to be. Dumbledore extends his hand over the water in the cave, which bubbles furiously until a chain emerges. Harry tugs on the chain and a boat surfaces, which they board to go where the light is hovering. There is a crystal plinth with a liquid in it, and Dumbledore announces that the only way to reach what is in the plinth is to drink all the liquid. He says he must drink, and Harry must force him to drink it, even if he forgets why he must drink or suffers intense pain. After one dose, Dumbledore collapses, but Harry keeps scooping the liquid up and coaxing Dumbledore to drink, even though it tears him apart to do so. When Dumbledore swallows the last, he recognizes Harry again, and asks wearily for water. But Harry finds none of his magic will get water to the headmaster, so he tries to take water from the pool in the cave.
Scores of Inferi, animated corpses (think multiple Gollum clones from "Lord of the Rings") scramble out of the water. Harry tries to fight them, both with magic and fists, but he is dragged underwater. Dumbledore is weakly reaching for his wand as Harry goes down, but above the water everything goes red, and the red shoots into the water to destroy any Inferi there. Harry swims up, finding Dumbledore standing in the midst of an inferno.
Back at Hogwarts, Draco rises from his hospital bed and dresses quickly. Bellatrix leads Fenrir and others into Borgin & Burke, while McGonagal and Snape both look at the darkening sky. Draco, in the Room of Requirement, opens the Vanishing Cabinet, although he looks sick.
In the Astronomy Tower, Dumbledore brings Harry back and asks the boy to find Severus. But they hear noises, and Dumbledore orders Harry to hide "below", pleading for Harry's trust. Draco enters, and shows Dumbledore his Dark Mark. Dumbledore points out that Draco's attempts to kill him have all been half-hearted, even though all did damage to different people. Draco disarms Dumbledore, but he is on the verge of tears and lowering his wand when Bellatrix and the other Deatheaters enter. In his hiding place, Harry sees Snape, who gestures for Harry to keep quiet and out of sight. Snape comes up, and Dumbledore softly says, "Severus. Please."
"Avada Kedavra!" Snape snaps, and Dumbledore takes a long, slow motion fall from the Astronomy tower. Bellatrix shoots the Dark Mark above the tower, and the Deatheaters rush into the Great Hall. Bellatrix is like a hyperactive kid, smashing the windows and plates and goblets. Draco is a wreck, crying but being tugged by Snape. They make their way out, and Bellatrix hits Hagrid's hut with a fire spell, and Harry rushes to them. Bellatrix attacks, but Snape says, "Leave him to the Dark Lord!" Harry tries to hurt Snape, even trying to hit him with Sectumsempra, but Snape coldly dismisses him. "Hit me with my own spells? I am the Half-Blood Prince." He then vanishes.
Harry returns to where Dumbledore's body has fallen. Most of the school is gathered, staring at the corpse as Harry gives in to grief. As Ginny tries to comfort him, Professor McGonagal and the students light their wands, and the light shimmers up to break the Dark Mark with a cascade of gentle radiance. Harry later visits the headmaster's office, seeing the half-moon spectacles resting closed on an open book, and the wand laid on the desk. McGonagal says that if Harry needs to talk, but he shakes his head. She then tells him that Dumbledore held Harry in high regard: "You should know... you meant a great deal to him."
Harry is then in the Astronomy tower with Hermione and Ron. He explains that the locket they recovered is a fake. It holds a note from "R.A.B." explaining that the locket was taken in the hopes of weakening Voldemort. Harry also tells them that Draco was lowering his wand, that "it was Snape." He then starts to talk about his plans, to seek out the other horcrux. He hopes to send them letters from time to time. Hermione replies that she's always admired Harry's bravery, but he "is a bit thick." She and Ron are going to go with him on this hunt.
As Harry watches Fawkes take a final flight above Hogwarts, he murmurs that he never realized how beautiful this place was, while Ron and Hermione come on either side of him.
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