Plot to assassinate Albus Dumbledore

The plot to assassinate Albus Dumbledore was a series of events that took place over the 1996–1997 school year at Hogwarts School of Witchcraft and Wizardry. These attempts on Albus Dumbledore's life were the events that led up to the Battle of the Astronomy Tower on 30 June, 1997. In the action, Dumbledore was killed by Severus Snape and not the primary perpetrator of the plot, Draco Malfoy.

Triwizard Tournament
In 1994, the Triwizard Tournament took place at Hogwarts School of Witchcraft and Wizardry. Two schools participated along with Hogwarts: Durmstrang Institute and Beauxbatons Academy of Magic. Lord Voldemort found out through Bertha Jorkins that the Triwizard Tournament was taking place that year. He also learned that Barty Crouch Jr. was still living and under the Imperius Curse by his father. However, he broke free of it and captured Auror Alastor Moody. Once the school year began, he began to impersonate Moody and teach Defense Against the Dark Arts to the students of Hogwarts.

Three students were picked to participate in the tournament from each school: Viktor Krum, Fleur Delacour, and Cedric Diggory. However, Crouch Jr. Confunded the Goblet of Fire to believe there were four schools entering, placing Harry's name under the fourth false school. Harry was forced to take part in all three tasks. Barty Crouch Jr. (disgiused as Alastor Moody) helped Harry through the first two tasks, and, before the third one (a giant maze with the Triwizard Cup in the middle) commenced, he offered to place the cup in the middle, and made it into a Portkey.

He monitored the maze and due to Moody's magical eye he was able to see through the maze. He stunned Fleur and imperiused Viktor. After that, Cedric stunned Krum. Cedric and Harry soon reached the cup, and decided to take the cup together, deciding that it would still be a Hogwarts victory.

Return of the Dark Lord
"Bone of the father, unknowingly given, you will renew your son. Flesh of the servant, willingly given, you will revive your master. Blood of the enemy, forcibly taken, you will resurrect your foe."

- Peter Pettigrew reviving Lord Voldemort

Immediately arriving to the Little Hangleton graveyard, Cedric Diggory was killed by Peter Pettigrew. Harry was tied to Tom Riddle Sr.'s grave and forced to watch (and help by being forced to give his blood) as Voldemort regained a rudimentary body. Voldemort's Death Eaters were called to the graveyard and he expressed his anger that nobody tried to find him.

Harry and Voldemort soon duelled, and they experienced Priori Incantatem. This happened because they shared the same wand core- a Phoenix feather. Harry saw echoes of his parents, Bertha Jorkins, Frank Bryce, and Cedric Diggory. They gave him time to get Cedric's body and return back to Hogwarts. He alerted the wizarding world of Voldemort's return, but the Ministry of Magic did not believe him.

Early stages
During the summer between his fifth and sixth years at Hogwarts, Draco Malfoy was tasked with the assassination of Albus Dumbledore. Also at this time, Draco was branded with the Dark Mark. This killed two birds with one stone for Voldemort. First, he would have another agent acting at Hogwarts. Second, Voldemort could punish the Malfoys for their failures, such as their disloyalty and failing to retrieve the prophecy from the Department of Mysteries.

The Unbreakable Vow
"Will you, Severus, watch over my son, Draco, as he attempts to fulfill the Dark Lord's wishes? And will you, to the best of your ability, protect him from harm? And, should it prove necessary... if it seems Draco will fail... will you carry out the deed that the Dark Lord has ordered Draco to perform?"

- Narcissa Malfoy on the conditions of the Vow

The news of Draco's assignment was leaked to a few Death Eaters including Draco's mother and Severus Snape. Wanting to keep Draco safe, Narcissa Malfoy sought out Severus Snape for help. Narcissa asked Snape to make an Unbreakable Vow, to which he complied. She asked him to follow three objectives:
 * 1) To watch over Draco as he tries to carry out the task
 * 2) To try to help him if needed
 * 3) If Draco is unable to carry out the task, to do it for him

Diagon Alley
Late in the summer, Draco visited Diagon Alley with his mother. While there he ran into Harry Potter, Hermione Granger, and Ronald Weasley in Madam Malkin's Robes for All Occasions. Harry noticed that Draco flinched when Madam Malkin attempted to touch his left arm. Afterwards, Draco gave his mother the slip and headed for Borgin and Burkes. While there he bullied Borgin to help him repair an unknown object and to keep the "other one" safe. He told Borgin that Fenrir Greyback would be checking in on his progress. This exchange was witnessed by Harry, Ron, and Hermione who had sneaked away from their escorts under Harry's Cloak of Invisibility. From their gathered information, Harry surmised that Draco Malfoy was now a Death Eater and was up to something, a fact debated by his friends.

First two attempts
The first attempt took place on 12 October, 1996, when Madam Rosmerta who, under the Imperius Curse, Imperiused Katie Bell and forced her to deliver a package containing an opal necklace to Albus Dumbledore. She was thwarted when she got into an argument with her friend Leanne. As Leanne tried to grab the package from Katie, it fell to the ground and opened. Katie accidentally touched the cursed necklace through a tiny hole in her glove and was dragged into the air, gracefully holding her arms aloft as in a cross. She then screamed terribly and fell to the ground. She was rushed off to the school by Hagrid. When questioned about the incident, Harry, Ron, and Hermione who had witnessed what had happened, Harry accused Draco Malfoy of cursing Katie, much to the chagrin of his friends. Katie was sent to St. Mungo's where she remained for months.

In the second attempt an Imperiused Rosmerta gave Horace Slughorn a bottle of mead to deliver to Dumbledore. Unbeknownst to Slughorn, it was poisoned. The attempt was thwarted when Slughorn unfortunately gave the mead to Ron Weasley on his seventeenth birthday, on 1 March, 1997. Harry Potter knew to shove a bezoar down his throat and saved him.

Horcrux Hunt
Albus Dumbledore was under the assumption that Voldemort had made Horcruxes. Due to this assumption, he asked Horace Slughorn to return to Hogwarts to teach Potions, believing that he held an important memory regarding Voldemort and his Horcruxes. After retrieving the memory from Horace Slughorn, he knew he was correct. He had already found a ring that was a Horcrux, but it held the Resurrection Stone in it. Forgetting that it was a horcrux, he put it on his finger, hoping to see his parents and little sister again. Thanks to his skill and Severus Snape's skill, Snape was able to hold off the curse from spreading. He gave him a year to live. Knowing that Voldemort had given Draco the task to kill him, and knowing that he would fail but not wanting his soul broken if he did, he asked Snape to do it instead. Snape reluctantly agreed.

Knowing his time was short, he set out to tell Harry everything he knew regarding the Horcruxes and Voldemort's quest to become immortal.

Horcrux Cave
Unknown to Snape, Harry or Dumbledore, Draco Malfoy had finished fixing the vanishing cabinet that night that happened to be the same day that Dumbledore and Harry would be travelling to recover and destroy the Horcrux. Dumbledore thought that a Horcrux may be at a cave that Voldemort's orphanage took him and the children when they were young. Harry, still stuck on his theory that Draco was a Death Eater, told Ron and Hermione that Draco would try to get Death Eaters into the school since Dumbledore was gone. He gave them his bottle of Felix Felicis, believing that he himself would not need it since he was with Dumbledore.

Harry and Dumbledore set off, finding the cave rather easily. Dumbledore discovered the entrance to the cave and found that in order to pass one had to pay in blood, Voldemort thinking this would weaken the drinker. The cave was massive and inside was a subterranian lake in complete darkness.. Walking round the edge of this cave, they saw a misty green lake far away in what appeared to be the middle of the cave, and somehow they had to get across when they realised there were monsters of some kind in the lake. Dumbledore then discovered that there was an invisible boat waiting for them, according to Dumbledore made that so only one wizard of age could occupy it. However, since Harry was underage, both of them were able to sit in it. The boat started moving on its own terms, and took them towards the green light which was on an island. The green light turned out to be a potion, that could only be drank by the person who had travelled across the lake. Harry and Dumbledore tried in vane to get what lied beneath the potion, Dumbledore decided that the only way to despose of it was to drink it. Dumbledore, telling Harry to force the potion down him, said it would not kill him but probably cause him severe pain, or make him forget why he was there. Harry argued, hating the idea of causing his mentor so much pain but relented. Dumbledore conjured a goblet and started drinking it, seeing nightmares and feeling severe stomach pains and dehydration while probably seeing the duel between him, his brother, and Gellert Grindelwald that led to his sister's death. This time Dumbledore protested against himself drinking the potion, but Harry managed to force it down him. Dumbledore. Severely weakened and feeling incredibly thirsty, Harry tried casting the Aguamenti Charm in the goblet, to no avail. Soon realised that Voldemort had made it so, Harry filled the goblet with water from the cave. The Inferi came and attacked, Harry unsuccessfully using Sectumsempra on them. Dumbledore recovered and intervened by using fire. Retrieving the locket that they assumed to be the Horcrux, they left the cave and arrived back in Hogsmeade. Madam Rosmerta alerted them that the Dark Mark had been cast over Hogwarts, and they immediately flew back after she supplied them with broomsticks.

Battle of the Astronomy Tower
"I've got to do it! He'll kill me! He'll kill my whole family!"

- Draco Malfoy attempts to kill Albus Dumbledore.

On 30 June, 1997, Dumbledore and Harry Potter left the school in search of one of Lord Voldemort's Horcruxes. Rosmerta saw Harry and Dumbledore heading through Hogsmeade village and informed Draco Malfoy. Dumbledore was greatly weakened by a potion he was forced to drink, during their adventure. He and Harry apparated back to Hogsmeade afterwards. Once Rosmerta informed Dumbledore of the Dark Mark above the school, he and Harry flew back to the school on Rosmerta's broomsticks. Once they had arrived, Dumbledore was cornered by Draco on top of the Hogwarts Astronomy Tower. He attempted to kill Dumbledore, but Dumbledore tried to convince Draco not to perform the task. Draco said that he had no choice. Otherwise, Lord Voldemort would murder him and his family. Dumbledore told Draco that he shouldn't do this, and that Draco was not a killer. He offered to protect Draco, but Draco did not accept, saying he had gotten so far, having been expected to die in the attempt. Then, all of a sudden, Death Eaters appeared in the room. They tried to convince Draco to carry out the task, but Draco seemed to not know what to do. Fenrir Greyback attempted to take over but was told not to.

"Severus... please..."

- Dumbledore's final words.

The teachers of Hogwarts and the members of the Order of the Phoenix who had been in Hogwarts Castle that night sent for Snape. They believed he could help them in the battle. After being summoned, Snape headed to the Astronomy Tower. Once he arrived, Draco lowered his wand. Dumbledore pleaded with him. Snape hesitated then cast the Avada Kedavra killing Dumbledore. After he killed Dumbledore, Snape ordered the Death Eaters out of the school and took Draco with him. They had to fight their way through the defenders of Hogwarts to get to the grounds. They were also pursued by Harry Potter who had been in a Full Body-Bind Curse the entire time. He caught up by the time the Death Eaters reached the grounds. In an attempt to avenge his fallen hero, Harry attempted to curse Snape, but Snape managed to disarm Harry, revealed that it was he, Snape, who was the Half-Blood Prince, and escaped before Harry could regain his wand.

Aftermath
Harry realised that the locket was fake and felt that everything had been for nothing. He told the professors that it was Snape who killed Dumbledore. They all agreed that Dumbledore deserved to be laid to rest at Hogwarts, and many people from the wizarding world attended, such as Cornelius Fudge, Rufus Scrimgeour, Dolores Umbridge, Madame Maxime, the Merpeople and Centaurs of Hogwarts, and many other witches and wizards.

Behind the scenes

 * Dumbledore had deduced that Draco was the one who cursed Katie Bell and poisoned the mead.
 * Curiously enough, Professor Trelawney had on more than one occassion been seen to have forseen the events on top of the Astronomy Tower through her card shuffling. She apparently was unaware of the actual tragedy, and if she had in fact forseen the omen or had made it up is unknown, but she had told her premonition to Harry after being thrown out of the Room of Requirment, though her warning fell on deaf ears. She referred to a "tragedy" on the "lightning struck tower", "coming nearer all the time!"

Appearances

 * Harry Potter and the Half-Blood Prince
 * Harry Potter and the Half-Blood Prince (film)
 * Harry Potter and the Half-Blood Prince (video game)
 * LEGO Harry Potter: Years 5-7