Chapter 10 of Harry Potter and the Deathly Hallows: Kreacher's Tale
Harry awakens in the early hours, pondering the daunting task Albus Dumbledore gave him and the tales about Albus' young life. Bored, he explores the mansion. On the second landing, the room Ron and Harry previously used has been searched, presumably by Death Eaters. Sirius Black's room on the next floor has also been searched; amid the mess is a handwritten letter from his mother to Sirius thanking him for the toy broomstick he gave Harry for his first birthday. A half-torn photo shows baby Harry riding the broomstick. The letter's second page is also missing, but the first one mentions Bathilda Bagshot, a famous wizard historian who often visits, and that Dumbledore borrowed James Potter's Invisibility Cloak. The letter ends halfway through Lily's sentence saying that she is, "surprised that Dumbledore..." Harry searches unsuccessfully for the second page.
Harry shows Hermione what he found and immediately wants to go to Godric's Hollow to meet Bathilda Bagshot and ask about his parents and the Dumbledore family. Hermione believes it is too dangerous and unrelated to their mission. Harry then notices Regulus Black's full name posted on a door; it matches the initials R.A.B. on the note found inside the fake Locket Horcrux. Hermione calls Ron then unlocks the door. Inside, they hunt for Slytherin's Locket, but find nothing. Hermione remembers a locket that no one could open and was tossed away. Harry suspects Kreacher, the Black family House-elf who was continually retrieving discarded items, may have hidden it.
Kreacher says Mundungus Fletcher stole the locket; he also tells them that when Voldemort required a House-elf, his master, Regulus Black, gave him Kreacher. At a lake inside a cave, Voldemort forced Kreacher to drink a potion from a basin that made him think horrible thoughts. Voldemort placed a locket into the emptied basin and refilled it with more potion. Kreacher, abandoned and in misery, crawled to the water to drink, only to be dragged under the surface. However, Kreacher, as ordered, returned to his master.
Regulus, rejecting Voldemort's beliefs, apparently discovered the Locket was a Horcrux and had Kreacher take him to the cave. Kreacher was ordered to force Regulus to drink all the potion, then to replace the real Locket with a fake one. After consuming the potion, Regulus, thirsty, drank from the lake, only to be pulled under by Inferi. Kreacher was unable to destroy the real Locket as he had been ordered. Because he was commanded to reveal nothing, Kreacher alone knew Regulus' fate. Kreacher, distraught over failing his master, sobs uncontrollably.
Harry, though still upset by Kreacher's part in Sirius' death, is bothered more by Voldemort exploiting Kreacher. Hermione explains House-elves are used to brutal treatment, so he never resented Voldemort's abuse. Also, from Kreacher's perspective, Sirius betrayed the Black family by leaving home. The Trio must now find the Locket. Harry wins Kreacher's allegiance by telling him that their mission is to destroy the Locket, as Regulus wanted. When he gives Kreacher the fake locket, Kreacher is overcome by receiving a Black family heirloom. Harry then orders the elf to fetch Mundungus. Kreacher Disapparates to find him.
While much information regarding the Trio's Horcrux quest is revealed, Harry's relationship to Number 12, Grimmauld Place, the house he inherited from Sirius Black, should also be examined. The house, which seems frozen in the past, provides the Trio a safe haven, and Harry was happy here during his brief visits with Sirius, but he hardly considers it home, nor does he now find it comforting; instead, its murky, decaying interior is filled with sad reminders of Harry's lost godfather who endured his own unhappy childhood there. Like the fugitive Sirius, who was long confined inside as the Ministry hunted him, Harry finds the residence to be as much a bleak prison as it is a protective refuge. Even its name reflects its grimness. The Trio must also contend with Kreacher, the belligerent House-elf Harry also inherited, and the fanatical Mrs. Black's screaming portrait. As depressing as Grimmauld Place might be, however, for now, it is secure and comfortable. It has also yielded a fortuitous, if unexpected, result: a clue leading to a Horcrux.
Although many readers correctly guessed the answer, one of the most intriguing mysteries in the series, R.A.B.'s identity, is finally definitively solved. Regulus Arcturus Black is arguably the most important unseen character in the series. Like Draco Malfoy, Regulus quickly learned that being a Death Eater required far more unpleasantness than he had ever imagined or could provide. And once recruited, there is no leaving the Dark Lord's service alive. Unable to escape with his life, Regulus instead devised the plan to steal what he clearly believed to be Voldemort's single Horcrux, certain he would be killed in the process, but dying in the belief that he had helped to thwart the Dark Lord.
More is also learned about Regulus' and Kreacher's characters, their relationship with each other, with Voldemort, and what motivated them. Until now, the fanatically faithful Black family House-elf has been seen only as a rather nasty and unpleasant servant who is forced by circumstance to serve Harry, and who, if possible, would probably use any means to expose him to Voldemort. Not only does Kreacher's story explain how Regulus recovered the Locket Horcrux, but it also spotlights the callous ill-treatment the Wizarding world inflicts upon enslaved House-elves, and what little regard there is for their well-being or personal rights.
Harry remains conflicted over Kreacher, repulsed and angry that he betrayed Sirius to Voldemort, but also sympathetic to how the House-elf was exploited by the Dark Lord. Hermione explains that House-elves expect to be mistreated, and Harry comes to understand that they are hapless pawns, often abused and misused at their master's discretion. Even the name "Kreacher" (creature) implies that he and other House-elves are considered as little more than domesticated animals, albeit intelligent talking ones whose sole purpose and identity is to serve their wizard masters. Although he appears to be a despicable, inconsolable (and half-mad) wretch, Kreacher's character has been molded by the maltreatment heaped on him over the years, and by anguish over having to conceal Regulus' fate, probably coupled with remorse for being involved in it, and failing to follow his Master's final orders. Like many wizards, Sirius also treated the House-elf poorly or indifferently, though their mutual loathing was a contributing factor. Under Harry's continued kind, gentle treatment, however, it is possible that Kreacher could be transformed; even by the this chapter's end, after a very short interaction with Harry, he already seems far more willing to do Harry's bidding than we have ever seen.
As a small side light here, we should note Kreacher's return to his master. After being pulled under the lake by the Inferi, Kreacher had "come back". He never explains, he simply says he had returned to his master. It is a fair supposition that he used the House-elf form of Apparition to do so, and perhaps it is just something that he naturally does and it therefore lacks a name. We already have seen that House-elves can Apparate within Hogwarts, where the school's protective charms normally prevent Apparition. Voldemort has presumably prevented Apparition in the Horcrux cave to force any would-be thieves into running the gantlet of the lake and the Inferi. Equally, however, he clearly has failed to prevent House-elves from Apparating in the cave. Whether this is an oversight on Voldemort's part, which would support the readers' belief in his discounting non-Human magic, or whether it is simply impossible for human spell-casters to prevent Elf Apparition, is unknown.
Lily's letter to Sirius Black is a typical thank-you note and unlikely containing anything Death Eaters would consider important. That makes it even more intriguing as to why only its second half is missing. What remains provides useful information for Harry, however. Lily mentions the elderly Bathilda Bagshot, a famous wizard historian who lives in Godric's Hollow, who Lily apparently was acquainted with, and may know much about the Dumbledore clan. Harry immediately wants to go to Godric's Hollow, not only to meet Bathilda and learn more about Dumbledore and his family from her, but also to see his birthplace. Hermione vetoes this, arguing that it is unrelated to their mission, too dangerous, and she suspects Voldemort may have set a trap there. Hermione instead encourages Harry to trust his own feelings and memories about Dumbledore, rather than believing malicious rumors and unsubstantiated innuendos spread by Ron's Aunt Muriel, Rita Skeeter, and others.
The letter also mentions that Dumbledore borrowed James' Invisibility Cloak, though for what purpose is still unknown. This reminds us that Dumbledore had this Cloak in his possession when James died, and perhaps is intended to pique the reader's curiosity as to why he might have wanted it. The letter is also significant in that it is probably the first time Harry has seen his mother's handwriting or read her own words. For Harry, who has tended to identify with his father more than his mother, it awakens new-found feelings that tie him closer to her. It also shows yet another means by which the dead are able to speak from beyond the grave and affect the living.
The torn photograph adds to the mystery. Presumably its missing half contained either James' or Lily's image, proudly watching their young son flying about on his first toy broomstick. Just why someone would take the ripped half is unknown, and certainly curious.
- Harry wants to meet with Bathilda Bagshot to learn more about Dumbledore. Who else might have been interested in talking to Bathilda about him and why?
- Why does Hermione tell Harry to rely on his own memories about Dumbledore, rather than what others have to say?
- How has Kreacher's behavior toward Harry changed? What might account for this?
- Why didn't Kreacher destroy the Locket Horcrux? Given what is known about Horcruxes and Elf magic, could he have destroyed it?
- Why is Harry both judgmental and sympathetic to Kreacher? What is Hermione's explanation and do Ron and Harry agree?
Further Study 
- Why would only the second page of Lily's letter's and her image from the photo be missing? Who might have taken them?
- What could Harry learn about his parents and Dumbledore from talking to Bathilda Bagshot? Would her revelations be any more truthful, accurate, or unbiased than anyone else's?
- Why does Hermione advise Harry against going to Godric's Hollow or talking to Bathilda Bagshot? Should Harry listen to her advice? Explain.
- Harry suspects Death Eaters searched Grimmauld Place. Why might that assumption be wrong? Who might have searched it and why?
- How did Regulus Black know that the Locket was a Horcrux? Why was he willing to forfeit his life to destroy it?
- Kreacher says the potion he was forced to drink made him think horrible thoughts. Based on what is known about his character, what might those thoughts have been?
- Why would Regulus drink the potion, knowing it was likely harmful, rather than order Kreacher or some other House-elf to do so?
Greater Picture 
The missing half of Lily's letter and the torn photograph are significant, though not in the way readers might expect. It was Snape who took the letter and the photo (with Lily's image), apparently for personal reasons rather than because they contained any vital information relating to Voldemort, Dumbledore, or the Order of the Phoenix.
The letter's mentioning that Dumbledore borrowed James' Invisibility Cloak is also significant. It will be learned that the Cloak is one of the three titular Deathly Hallows. Dumbledore's wand is another Hallow, and he was searching for the third, apparently hoping that the three Deathly Hallow's legendary ability to conquer death would reunite him with his lost family.
It is never explained how Regulus discovered that the Locket was a Horcrux. He also apparently never understood how to dispatch one, as he only directed Kreacher to take and destroy it, apparently assuming any strong magical charm would do the job. Kreacher, unable to destroy it with conventional magic, merely kept it. Harry has already learned, by means of Hermione's research, that there are only a few methods to destroy these Dark magical objects, and he must find some alternative means to eliminate Voldemort's Horcruxes. Like Regulus, Harry will likewise task someone (Neville Longbottom) to kill the last Horcrux in the event that he, Ron, or Hermione are unable to during the Battle at Hogwarts. Harry, unfortunately, neglects to instruct Neville on just how to accomplish this, leaving Neville to his own devices.
Kreacher being able to easily Apparate in and out of Voldemort's highly secure sea cave demonstrates how Elf magic differs from wizard magic. This ability, which we have now seen several times in Hogwarts, will be seen again in a later chapter when Dobby rescues the imprisoned Trio and several others by Apparating into a magically protected area. This ability also underscores a major weakness in Voldemort—a failure to consider that anyone he considers inferior could actually be more powerful magically.
Also, Hermione's fears about Godric's Hollow will prove to be well-founded, though it will later be her idea to go there.