<P> After being sent an invitation to the funeral for Aragog the Spider, he uses an hour's dose of Felix Felicis and succeeds in retrieving Slughorn's unedited memory while at the funeral . In it, Slughorn tells Riddle about the process of splitting one's soul and hiding it in several objects called Horcruxes . Only by committing a murder can a wizard turn an object into a Horcrux; Voldemort has created six of them, making himself virtually immortal by placing a piece of his soul in each and keeping the seventh and last one within his body . Dumbledore explains that in order to destroy Voldemort, all the Horcruxes must first be destroyed . Two Horcruxes--Riddle's diary from Harry Potter and the Chamber of Secrets and a ring belonging to Voldemort's grandfather Marvolo Gaunt--have already been destroyed, but four others remain . </P> <P> As Harry learns more about his great enemy, the love lives of the main characters start to become more active . Ron and Hermione grow closer together, but after learning from his sister Ginny that Hermione had previously kissed Viktor Krum, Ron shuns her . Harry's attempts to repair things between the two fail, resulting in Ron going out with Lavender Brown and making Hermione jealous . After Ron is nearly killed in an attempt on Dumbledore's life, he and Hermione reconcile . Ron and Lavender break up when Lavender sees the two of them walking out of the boys dormitories together . However, this was only because she hadn't noticed Harry walking ahead of them . Harry develops feelings for Ginny, but is reluctant to pursue her for most of the year because of his friendship with Ron . Following a wild Quidditch victory Harry and Ginny finally strike up a relationship, with Ron's reluctant consent . </P> <P> Near the end of the year, Harry and Dumbledore journey to a cave to retrieve a suspected Horcrux, Slytherin's locket . Dumbledore expertly finds a secret passageway to a large, pitch black underground lake, which Harry and Dumbledore cross in a small boat to an island in the centre . The locket is at the bottom of a basin and can only be reached by drinking the potion above it . Harry helps Dumbledore, who drinks the potion, and though Dumbledore is severely weakened, together they manage to fight off Voldemort's Inferi that have been hiding in the lake . They take the locket and return to find that the Dark Mark has been placed over the highest tower in Hogwarts in their absence . Harry and Dumbledore ascend the tower where they are ambushed by Draco Malfoy, accompanied by Death Eaters that he helped get inside Hogwarts . Dumbledore freezes Harry under his Invisibility Cloak with a body - bind spell to keep him hidden . Draco disarms Dumbledore of his wand and then threatens to kill him, which turns out to have been his mission from Voldemort . Draco is unable to go through with it, and Snape arrives and casts the spell to kill Dumbledore instead . Harry ignores the battle raging in Hogwarts to pursue Dumbledore's killer . Snape successfully fights Harry off, and he reveals that he is in fact the Half - Blood Prince before he, Draco, and the rest of the Death Eaters escape . </P> <P> After Dumbledore's funeral, Harry decides to break up with Ginny, saying it is too dangerous for their relationship to continue . Harry finds out that the locket is not the real Horcrux, containing only a note from someone named "R.A.B.". Harry is so devastated by Dumbledore's death (and upset by its futility) that he tells his friends he will not be returning to Hogwarts and will instead spend the next year searching out Voldemort's Horcruxes . Ron and Hermione insist on joining him in destroying Lord Voldemort for good . </P>

Harry potter and the mystery of the prince