Harry reports to Dumbledore’s office. Dumbledore explains that he is going to teach Harry more about Lord Voldemort and hopes this information will ultimately help Harry survive. They gather around the Pensieve, a shallow stone basin that allows its users to experience the memories of others. Dumbledore takes a small vial of memory from his robe and tells Harry that they are going to view one of Bob Ogden’s memories. Ogden worked for the Department of Magical Law Enforcement. Suddenly, Harry and Dumbledore are standing in a country lane, watching a plump man in glasses read a wooden signpost. Ogden cautiously approaches a house. As Ogden nears the house, Harry hears a voice speaking Parseltongue, the ancient language of snakes, telling Ogden he is not welcome. The voice, coming from Morfin, a man in rags, moves closer and jinxes Ogden. Suddenly, another man rushes out of the cabin—it is Morfin’s father, Gaunt. Ogden tells the men that he is here to investigate Morfin’s use of magic on a Muggle.
Ogden meets Gaunt’s daughter, Merope. Ogden presents a summons to the Ministry for a hearing, and Gaunt reacts with rage, first showing Ogden his ugly gold ring with a black stone, then dragging Merope toward Ogden by the locket hanging around her neck. Gaunt shows Ogden the symbol on the locket, explaining that they are the last living descendents of Salazar Slytherin. Gaunt admits that his son performed a jinx on a Muggle, and Morfin accuses Merope of being in love with the Muggle boy, Tom, whom he jinxed. Gaunt erupts into anger, screaming at Merope with disgust and attempting to strangle her, which Ogden prevents using magic. Morfin hops up, wielding a knife and his wand, and Ogden flees the house.
Dumbledore and Harry return to Hogwarts. Dumbledore tells Harry that Ogden Apparated back to the Ministry and returned with reinforcements. Morfin and Gaunt were arrested and sentenced to time in Azkaban—six months for Gaunt and three years for Morfin. Gaunt’s first name, Dumbledore explains, was Marvolo, which Harry recognizes as the name of Voldemort’s grandfather. Harry concludes that Merope must be Voldemort’s mother. Voldemort’s father, Dumbledore continues, was Tom, the Muggle boy Morfin jinxed. Merope used a love option on Tom, and when Marvolo returned from Azkaban he would not speak to or acknowledge his Muggle-loving daughter. Within a few months of their marriage, Tom returned to his Muggle village, presumably after Merope’s love potion wore off. Meanwhile, Merope was pregnant with Voldemort. Harry asks Dumbledore if it is acceptable for him to share this information with Ron and Hermione, and Dumbledore gives his permission.
On his way out, Harry notices the black and gold ring, the same ring Marvolo showed Ogden and that Dumbledore was wearing when he collected Harry from the Dursleys. Dumbledore tells Harry he acquired it recently, around the same time he injured his hand. Hermione notices that Dumbledore’s seat in the Great Hall has been empty frequently. At Quidditch tryouts, Harry picks Ron as Keeper, despite his inconsistent performance history. After tryouts, Harry, Ron, and Hermione head down to Hagrid’s cabin. Hagrid is angry with the students for not taking his class, but he finally forgives them when Hermione offers to go with Hagrid to visit his giant spider friend, Aragog, in the forest. Hagrid declines, claiming that the rest of the tribe would eat any visitor other than Hagrid, but he is cheered by the offer. Professor Slughorn invites Harry and Hermione to a small party for his favorite students in his room. Harry declines because he has to make up a detention with Snape, but Hermione agrees to attend.
When Dumbledore invites Harry into the Pensieve, he is granting Harry exclusive access to Voldemort’s childhood in the hopes that Harry will better understand Voldemort’s habits and tendencies and eventually be able to use that information to destroy Voldemort forever. In their first trip into the Pensieve, Harry witnesses the Gaunts, a despicable family obsessed with their Pureblood Slytherin lineage and with maintaining a Mud-free line. The Gaunts treat each other very badly and extend their lack of goodwill to their neighbors. Clearly, Marvolo and Morfin are at war with the Muggle families living nearby and can think of nothing worse than Merope falling in love with a Muggle man. Marvolo and Morfin finally end up in Azkaban thanks to the intervention of the Ministry, but Harry is surprised to find himself feeling almost sympathetic toward Voldemort’s mother, Merope, who was forced to endure constant abuse from her father and brother. Merope falls in love with a Muggle man, and it seems possible that her feelings are as much a result of wanting to escape her terrible family as anything else. Merope may have a crush on Tom, but her desires are certainly rooted in a desire to betray and anger her terrible relatives. Because Tom has no reason to reciprocate her feelings, Merope is forced to administer a love potion, and when it wears off, she’s left pregnant and alone. We can sympathize with Merope’s plight, despite her terrible father and brother.
Rowling continues to underscore the importance of friendship. Dumbledore agrees that it would be wise for Harry to share the new information about Voldemort with Ron and Hermione, suggesting the necessity of collaborative thinking and action. At Quidditch tryouts, Harry picks Ron as Gryffindor Keeper, even though he knows that Ron is an extremely inconsistent player. Still, Harry would rather protect the feelings of his best friend that choose a Keeper who may perform more reliably. Luckily for Harry, Ron performs quite well at tryouts, so Harry’s moral dilemma dissipates. Later, Hagrid also calls on his young friends for their loyalty and support. Even though Ron and Harry are horrified by the prospect of visiting Aragog, Hagrid’s giant spider-friend, Hermione offers to accompany Hagrid, which makes him feel loved and cared for. He turns down their offer, but Hermione’s willingness to make the trip was more than enough to satisfy Hagrid’s desire for friendship and support.