Dumbledore takes Harry to the home of Horace Slughorn, former Potions teacher at Hogwarts, and persuades him to return to teach. Harry is taken to the Burrow, where Hermione has already arrived. The next morning they get their O.W.L. results, and school supplies lists. Later, Ron Weasley and Hermione Granger follow Draco to Dark Arts supplier Borgin and Burkes. Harry is instantly suspicious of Draco, whom he believes to be a Death Eater. The students return to school, where Dumbledore announces that Snape would be teaching Defence Against the Dark Arts this year, while Slughorn would resume his post as Potions teacher. Harry now excels in Potions, thanks to having received a used Potions textbook that once belonged to someone named …show more content…
They reach the basin where the Horcrux is hidden underneath a potion. Dumbledore drinks the potion and is severely weakened by the potion as Harry fights off Voldemort's Inferi. They take the Horcrux, Slytherin's locket, and return to find that the Dark Mark has been placed over Hogwarts in their absence. Dumbledore uses his magic to freeze Harry in place while Harry remains hidden by his cloak of invisibility. When Draco arrives, he disarms and threatens to kill Dumbledore, acting on his mission from Voldemort. Dumbledore tries to stall Draco, who is unable to go through with it, but Snape arrives and kills Dumbledore. Because of Dumbledore's death, his spell on Harry is broken and Harry rushes after Snape to avenge Dumbledore. Snape reveals that he is the Half-Blood Prince and escapes with the other Death Eaters who had infiltrated the school. Later, Harry finds out that the locket is not the real Horcrux, containing only a note from someone named "R. A.