Muggles' Guide to Harry Potter/Major Events/Tower Battle (Hogwarts)

Overview
Harry and Professor Dumbledore, returning from a mission to retrieve a Horcrux, find the Dark Mark floating over the school's Astronomy Tower. Reaching the top of the tower, a weakened Dumbledore sends Harry down for help, but Petrifies Harry when he hears someone coming. Harry helplessly watches as Draco Malfoy, arrives and immediately disarms Dumbledore. Dumbledore determines that Draco is there to kill him, and almost manages to talk him out of it, when four Death Eaters enter the scene and start egging Draco on. Finally, Severus Snape reaches the top of the tower, and kills Dumbledore.

As the Death Eaters retreat down the staircase, Harry Petrifies one of them. As he reaches the main floor, he finds a few members of Dumbledore's Army and a few members of the Order of the Phoenix battling Death Eaters, and hears Snape call the Death Eaters off. Harry chases Snape and Draco, but although he is nearly able to catch up to them, he is unable to Jinx Snape. The Death Eaters escape, and Harry must return to the school and explain what had happened.

Event Details
Harry Potter and Albus Dumbledore return to Hogsmeade from their quest to find a Horcrux. Dumbledore is very weak from the after-effects of potion, and is asking Harry to get Severus Snape for him. They are met in the street by Madam Rosmerta, who alerts them of the Dark Mark floating above the Astronomy Tower at Hogwarts. Harry summons brooms from inside the Three Broomsticks, and flies with Dumbledore to the Astronomy Tower. Once at the top of the tower, Dumbledore is too weak to head down the stairs to the battle. He sends Harry, concealed by his Invisibility Cloak to fetch Snape, but before Harry can reach the door, footsteps are heard approaching the door from the other side, and Dumbledore immobilizes Harry.

Draco Malfoy, bursting onto the scene, disarms Dumbledore, and Harry must look on silently as Dumbledore almost convinces Malfoy to change sides. Dumbledore correctly determines that Draco is motivated by fear for his family and himself, and plays on that, and his understanding that Draco is not totally evil.

Four Death Eaters now arrive, and approach a weakened Dumbledore. While they jeer at Draco and try to egg him on, he seems, at the end incapable of killing Dumbledore. The Death Eaters also refrain from killing Dumbledore, as they have apparently received instructions from Voldemort that this is Draco's job, that he must do it on his own.

Finally, Snape arrives, and kills Dumbledore. The Death Eaters turn to leave; Harry finds himself freed from the body-binding spell and runs after them, Petrifying one as he hurries to catch Snape. Snape has sounded the retreat, and the Death Eaters are now fighting a rearguard action as they head out of Hogwarts. Harry has to guess whether Snape and Draco are intending to try to exit through the Room of Requirement, that being how they had gotten in, or through the front door. Guessing, he uses every shortcut he knows on the way to the front door, seeing bloody footprints to reassure him he is headed in the right direction. As he exits the front doors, with Snape and Draco before him, and several other Death Eaters behind, he tries to Jinx Snape several times but is repeatedly blocked. One of the Death Eaters behind him Curses him, and he falls and loses his wand, but the curse is stopped by Snape, who says that Voldemort wants Harry for himself.

The Death Eaters leave the school and vanish outside the gates. Harry helps Hagrid extinguish his burning hut, and returns to where Dumbledore's body lies. There, he recovers the locket Horcrux that he and Dumbledore had found, and discovers that it is not a Horcrux at all, but instead contains a note from one "R. A. B." who had evidently already retrieved the Horcrux and left this locket in its place. Ginny guides Harry up to the Hospital Wing, where Harry relates the events of the top of the Astronomy Tower to Professor McGonagall and the others gathered there.

In the aftermath, we learn that casualties were light; a large blond Death Eater, identified in a later book as Thorfinn Rowle, had been flinging Killing curses around randomly and had hit his fellow Death Eater, Gibbon. On the Order of the Phoenix side, apart from Dumbledore, the only casualty was Bill Weasley, who had been bitten severely by an un-transformed Fenrir Greyback and would likely retain facial scars for the rest of his life. The toll would almost certainly have been higher except for Harry's forethought in setting Ron, Ginny, and Neville Longbottom to watch the Room of Requirement, and giving Ron and Ginny some of his precious Felix Felicis potion. Draco, finding the room watched when he had emerged, had used Instant Darkness powder to prevent Ron, Ginny, and Neville from seeing the Death Eaters entering, but had luckily not Jinxed any of them. The students had luckily managed to find Remus Lupin, who had brought the Order members at the school, Professor McGonagall, Tonks, and Bill Weasley, into the battle. Professor McGonagall had sent Professor Flitwick to fetch Snape; Hermione and Luna Lovegood, stationed outside Snape's office, had heard something fall, and Snape, spotting them as he departed, said Flitwick had fallen and they should take care of him. The combatants in the hall under the Astronomy Tower had let him go past, thinking he was one of them, and had tried to follow him up the tower where the Death Eaters had gone, but the magical barrier across the stairs, which Snape had passed as if it were not present, still stopped the Order members. When Snape had returned down the stairs with Draco, the Order members, believing he was on their side, had again allowed him to pass unmolested.

Notable Consequences
Dumbledore is killed. Another of Harry's defenders and father figures has passed; Harry decides that he is not going to shield himself behind anyone else, he is going to have to tackle Voldemort himself, directly. This marks a vital stage in Harry's increasing maturity; rather than accepting guidance from others, Harry decides he will now choose his own path.

With the death of Dumbledore, the Headmaster's job will also be open. Whether this post will be offered to Professor McGonagall, currently the Deputy Headmaster and acting Headmaster in Dumbledore's absence, or not is as yet uncertain; it is the Board of Governors who appoint the Headmaster, and it is by no means certain that McGonagall, a Gryffindor, will be appointed following Dumbledore, who was apparently also a Gryffindor.

Now that Snape has effectively declared his loyalties and fled, the position of Defence Against the Dark Arts teacher is again available. With Snape's departure, Professor Slughorn will become head of Slytherin house. Slughorn, though a Slytherin through and through, is not a Voldemort partisan, and may be somewhat less likely to encourage Slytherin students to follow him.

Draco Malfoy has declared himself to be firmly on the side of Voldemort. However, he has also funked the job he was given. His father, Lucius, has now failed Voldemort three times, first by using the diary Horcrux irresponsibly and having it be destroyed, then by being involved in the failed plot to retrieve the Prophecy which ended with Bode being left insane, and finally failing to retrieve the Prophecy despite having twelve Death Eaters against six students, and incidentally alerting the Wizarding world to Voldemort's return, and getting himself imprisoned in Azkaban. Voldemort expects Draco to fail, as we see when his mother Narcissa visits Snape early in the book. Narcissa, at that point, hopes that if Dumbledore dies, whether it be by Draco's hand or Snape's, that Draco will at least have a chance to survive. However, the outcome of the battle will lower the Malfoy family in Voldemort's estimation, as now the two remaining Malfoy family members have failed him: Narcissa by talking to other Death Eaters about Voldemort's plans, and Draco by failing to carry out orders.

Harry determines that Dumbledore had believed in Snape's loyalty because Snape, having reported the Prophecy concerning Harry to Voldemort, had then returned to Dumbledore and informed Dumbledore of his actions.

Bill's injury, while not fatal, is disfiguring, and Mrs. Weasley assumes that it will mean the end of the planned wedding between Bill and Fleur. Fleur angrily denies this, however, and takes over nursing Bill from Mrs. Weasley. This revelation that there are unsuspected depths to Fleur wins Mrs. Weasley over. Until now, she had been putting up with Fleur solely for Bill's sake; now, she finally fully accepts Fleur as daughter-in-law.

In the aftermath of the battle, Remus Lupin and Nymphadora Tonks re-open what is apparently an old conversation for them, as to whether they should marry. Lupin believes that it is not a safe time to bring a child into the world, but Arthur Weasley, perhaps surprisingly, comes down on Tonks' side of the argument, saying there never is a completely safe time. It appears that this may be enough to sway Lupin, as we will later see that Tonks is once again looking animated, and her hair color is returning to its earlier wild shades.

Analysis
One of the keys to an extended story such as the Harry Potter series is that the reader must care about the hero. When the story is extended and episodic, the challenges that the hero faces must increase over time, so that despite his increasing strength, the reader feels that the hero is still challenged to the very brink of his abilities at each new crisis. In this one battle, we see Harry's greatest challenge to date, namely Severus Snape, who overtly declares himself a Death Eater by killing Dumbledore, and who then repeatedly thwarts Harry's attempts to attack him. Yet Harry manages to survive where Dumbledore did not. Looking back on this battle, of course, we see that Harry was not heavily involved; he seems to be at least partly protected by Snape, who says that Voldemort wants Harry for himself. Where Harry's strength is called for is not his physical or magical strength, but his strength of mind. He must support the weakened Dumbledore from the cave and back to the school, he must function despite witnessing the death of Dumbledore, and he must persevere to make plans for the eventual direct battle against Voldemort.

The death of Dumbledore, who until now had seemed indestructible and imperturbable, seems to put Harry entirely on his own; with Dumbledore gone, Harry's last apparent protector is gone. The readers can see that this is not entirely true; both Ron and Hermione volunteer to come with him and assist in the struggle to come. But while Ron and Hermione are of age, none of them have completed school yet, none of them are at their full powers. Is this going to be enough? We cannot know. It is certain that with Dumbledore gone, Voldemort's path to power is almost unobstructed.

For one who has made any study of heroic fiction of this nature, Dumbledore's fall, though saddening, is not unexpected. The hero must, in the end, proceed alone; with others shielding him, he cannot be a hero, after all. One of the major strengths of this particular instance is the nature of Dumbledore's fall, killed by one that he trusts, and has repeatedly said that he trusts. One fixed point in the series to this point is how consistently Dumbledore has been right. Up to this point, Dumbledore has made very few mistakes, though of course at the end of Harry Potter and the Order of the Phoenix, he does admit to a fairly large error of omission, which he then proceeds to rectify. Now, he is seen to have made an extremely major error, in trusting Snape. We don't yet know what effect this will have on Harry's feelings towards Dumbledore, and the mission that Dumbledore has apparently left Harry to complete.

Greater Picture
The Board, now likely dominated by Death Eaters, will want to put one of their own into Hogwarts as headmaster, and Voldemort, who has long wanted control of Hogwarts, will want to put one of his most trusted servants into that position. Professor McGonagall will remain at the school, but it will be Severus Snape, his fortunes restored by the fall of the Ministry to Voldemort and the subsequent demonization of Harry, who will become headmaster. Death Eaters will be placed in the school as instructors of Defence Against the Dark Arts and Muggle Studies, topics in which Voldemort wishes to change the agenda to suit his own ambitions.

It is only in Harry Potter and the Deathly Hallows that we learn the truth of this particular battle. It is there, in Snape's memories, that we learn that the events on the tower top had been, to a certain extent, planned. Dumbledore knew that the curse which had withered his wand hand was only contained for a while, and within a year would break free and kill him. He also had known that Voldemort had ordered Draco to kill him. With these two things in mind, Dumbledore had arranged that when Draco tried and failed to kill Dumbledore, Snape would finish the job. It is worth mentioning that this conversation occurs prior to the Unbreakable Vow Snape made to Narcissa Malfoy, so that the vow simply reinforces what Snape had already promised Dumbledore. Dumbledore had also requested that Snape "take care of his school"; Snape's becoming Headmaster may have been in part due to Snape's own politicking within the Death Eater organization to secure that position for himself pursuant to Dumbledore's wishes. He would, however, probably not have needed to politick much; as a long-serving, experienced teacher and head-of-house, and (in the Death Eater's eyes) the only one from this number to be a Death Eater, he was pretty much the natural candidate (which Dumbledore knew).

Learning, at the same time, why Dumbledore had trusted Snape, we will come to understand that Snape was worthy of the trust Dumbledore had placed in him, right to the end. Harry's understanding of why Dumbledore trusted Snape is correct, but incomplete; he, and we, will discover the full reason for Snape's revealing Voldemort's intent to Dumbledore in the final book.