Chapter 10 Summary
Harry awakens in a sleeping bag on the floor. He is filled with distressed thoughts about Dumbledore and wonders if the worst rumors the Rita Skeeter revealed in her article are true. Harry “could not stand lying there with nothing but bitter thoughts for company,” so he begins exploring Grimmauld Place.
Harry enters Sirius’ room and sees some sentimental items that belonged to Harry’s godfather before his death. Most importantly, Harry finds a letter from Harry’s mother to Sirius about Harry’s first birthday. Only half of the letter remains, however. Because Bathilda Bagshot is mentioned in the letter, Harry thinks that the second half of the letter must be very important and wants to go to Godric’s Hollow to find out as soon as possible.
On the way back downstairs, Harry notices the room of "Regulus Arcturus Black." Harry, Ron, and Hermione wonder if this is the R.A.B. who wrote the note inside the fake Horcrux locket. Sirius had a Death Eater brother named Regulus; however, something must have happened to turn Regulus against Voldemort. Trying to find the real Horcrux locket that R.A.B took, Hermione remembers seeing one when they were cleaning out Grimmauld Place long ago. Even though she remembers throwing it away, Hermione also knows that Kreacher, the house elf, often took many things out of the trash. The three look through Kreacher’s things but cannot find the locket.
Harry finally calls Kreacher. Kreacher has to appear because Sirius left Harry Grimmauld Place, including the house elf that goes with the home, in his will. Harry demands that Kreacher tell them all about the locket. It turns out that Kreacher does have the locket, but it was stolen by Mundungus Fletcher.
Kreacher then tells the three of them the entire story. Regulus, while he was still a Death Eater, ordered Kreacher to do everything Voldemort said to do and then go home to the House of Black. Voldemort took Kreacher to an island and made him drink poison from a basin so that Voldemort could drop his Horcrux inside the basin and then refill it with poison. Kreacher was left on the island to die, but because he is a house elf and was ordered to go home after helping Voldemort, Kreacher is able to apparate home. After Regulus becomes disenchanted with Voldemort, he has Kreacher return them both to the island. Regulus drinks the poison this time so that Kreacher can take the real Horcrux, destroy it, and replace it with a fake. Kreacher, of course, cannot destroy the Horcrux.
Harry gives Kreacher the fake Horcrux locket as a memento. Kreacher is touched by this kindness and promises to find Mundungus Fletcher for Harry, Ron, and Hermione. Kreacher disapparates to find Mundungus.