Kreacher admits that he did steal the locket after it was thrown out two years ago, but he says that it’s now gone—stolen by Mundungus Fletcher. Kreacher refers to the locket as “Master Regulus’s,” and Harry demands to know why, ordering Kreacher to tell them everything he knows about the locket.
Kreacher explains that after Sirius ran away from home and deserted his parents, Sirius’s younger brother Regulus (who had always been fond of Kreacher) became more and more involved in the Dark Arts. At the age of sixteen, Regulus joined Lord Voldemort. A year later, Regulus informed Kreacher that Lord Voldemort needed the services of a house-elf, and that Regulus had volunteered Kreacher, who then went to Voldemort to do his bidding.
What Voldemort needed Kreacher for was to test the defenses that he had set up to guard the locket Horcrux in the underground cavern—the defenses Harry and Dumbledore had encountered at the end of Harry Potter and the Half-Blood Prince. Voldemort made Kreacher drink the potion in the basin until it was all drunk, then he put the locket Horcrux in it and refilled it. Then Voldemort left Kreacher to die as the potion overpowered Kreacher with thirst, Kreacher went to drink from the lake, and the dead hands of the Inferi dragged him under the water.
But Voldemort seriously miscalculated by not taking into consideration the nature and ways of house elves. Kreacher had been ordered by his master Regulus to come back after helping Voldemort, so he was bound to return. More important, though no witch or wizard could Disapparate into or out of the cavern, house-elf magic works differently than wizard’s magic, so Kreacher was able to simply Disapparate from under the water, going back to his master Regulus.
Apparently, Regulus soon after had a change of heart about serving Voldemort, and he made Kreacher take him back to the underground cavern and show him the basin with the locket. Regulus drank the potion himself, stole the locket, and replaced it with the false one signed “R.A.B.” that Harry found. He ordered Kreacher to return home, never to reveal to Regulus’s family what had happened to him, and to destroy the locket, after which Kreacher saw Regulus dragged beneath the lake and killed. Kreacher returned to Grimmauld Place, unable ever to tell Mistress Black what had happened to her son, and unable to destroy the locket as ordered because of the powerful enchantments protecting it.
Though Harry nurses a grudge against Kreacher for betraying Sirius previously, Hermione forces Harry to see that Kreacher’s behavior has been both consistent and loyal, because Regulus never explicitly explained to Kreacher that he had changed his loyalties, and Sirius seemed to have betrayed his own family and household in leaving.
Harry orders Kreacher to find Mundungus Fletcher and bring him back to Grimmauld Place, but before Kreacher leaves, Harry presents him with Regulus’s false locket as a token for Kreacher to remember his former master by. Overcome with gratitude, Kreacher leaves to carry out Harry’s orders.
Kreacher does not return as fast as Harry hopes he will. He does not return that afternoon, or the next day, or the day after. Through the windows, Harry can see that Death Eaters are posted outside of the house, presumably watching for anyone entering or exiting.
The Death Eaters know the house is there, and that Harry owns it, because the Ministry of Magic has copies of every wizard’s will, but they can’t see it or enter it because of the enchantments on it.
Lupin arrives with news of the outside world. Harry is wanted for questioning by the Ministry. Wizards are being ordered to submit to interviews to prove they have wizarding parents. Anyone practicing magic who does not have wizarding parents (i.e., so-called “Mudbloods” like Hermione) will be presumed to have stolen magical secrets and will be liable for prosecution.
Lupin offers to accompany the three friends on their quest and provide protection, even if they are unable to tell him exactly what they are up to. He reveals that his wife Tonks is pregnant and staying at her parents’ house for safety, and admits that he regrets marrying her and bringing a half-werewolf child into the house, as the child will likely be an outcast.
Harry rejects Lupin’s offer angrily, calling Lupin a coward for seeking to abandon his own child. Lupin departs.
Still shaking with anger, Harry reads a newspaper Lupin left behind that contains an extract from Rita Skeeter’s biography of Dumbledore. Bathilda Bagshot is quoted, describing how Dumbledore’s mother, Kendra, shunned contact with other wizards when she relocated to Godric’s Hollow, and kept Ariana, Dumbledore’s sister, well out of sight. According to Bathilda, no one ever saw Ariana manifest any magical ability, so presumably she must have been a Squib.
Kreacher arrives with Mundungus Fletcher. Under forceful questioning, Mundungus admits that he stole the locket and was trying to sell it in Diagon Alley, when it was confiscated by a toadlike woman from the Ministry of Magic wearing a bow on her head—clearly Dolores Umbridge.
Chapters Nine–Eleven move the quest plot forward by unraveling the mystery of the locket in a vivid and highly dramatic fashion. The fake locket signed “R.A.B.” was the biggest mystery (and biggest frustration) of the year before, when Harry and Dumbledore went through the harrowing ordeal of getting to the locket only to find that someone had been there before them. In finding out what actually happened to the locket, we are treated to the fascinating story of Regulus Black, a Death Eater and Slytherin who turned out to be much more than he seemed. With this information, they have at last picked up the trail of a Horcrux and can pursue the trail to find the actual locket.
The characters did not have to do a lot of detective work in order to solve the locket mystery. They simply stumbled on a sign with a name that matched the initials. What they did that was significant was to change their attitudes toward Kreacher, the house-elf. Harry had previously been repulsed by Kreacher because of his appearance and because of his apparently bigoted and pureblood viewpoint, whereas Hermione, as early as Harry Potter and the Goblet of Fire, had pursued a misguided agenda of treating house elves like humans and promoting giving them rights to pay, vacation, benefits, and so on. What both Harry and Hermione together manage to do in these chapters is to see Kreacher clearly, as someone who is not a human being with a point of view of his own, but a creature whose very nature is defined by his loyalty and service to his master. When they see Kreacher for what he is and respect him for it, the door is unlocked, and Kreacher becomes extremely helpful to them.
The plot developments of these chapters come along with a general meditation on loss and mourning. The entire house is a memorial to Sirius, who left it to Harry and whose room is exactly as it was during Sirius’s Hogwarts days. The traces of Harry’s other friends and the time they spent there are everywhere. The photograph and letter that Harry finds, relics of his own parents, do nothing to advance the quest plot but do much to promote Harry’s sense that dead loved ones can reach out from the grave to communicate. This time that Harry spends pondering the loss of loved ones primes him to become furious with Lupin for what Harry perceives to be Lupin’s abandonment of his own unborn child. For Harry, nothing is more important than the loved ones he has lost.
As soon as Lupin leaves, Harry is once again plunged into doubt and torment about Dumbledore when he reads the excerpts of Skeeter’s book. Where the letter from his mother seemed to speak to him in her voice from beyond the grave, Dumbledore is communicating no clear message on his own behalf, instead causing doubts and frustrations. And Skeeter’s book, while adding no fresh rumors to those he heard from Aunt Muriel, only keeps Harry’s doubts alive. Harry isn’t just grieved by Dumbledore’s loss. Without actually admitting it to himself, he feels abandoned and betrayed by Dumbledore, just as Lupin is abandoning and betraying his wife and child.