Percy refuses to leave Fred's body. A giant spider climbs through the hole and Harry curses it. He and Ron begin to shoot curses down on the other spiders, help Percy move Fred's body into a hidden niche, and then Hermione pulls Ron and Harry behind a curtain. Ron is furious and wants revenge, but Hermione pleads with him that they need to find Nagini. She tells Harry to look inside Voldemort and figure out where he is and Harry obeys. Voldemort is in the Shrieking Shack and thinks that the diadem is safe. He tells Lucius Malfoy that he doesn't care about Draco and says that Harry will come to him soon. He then sends Lucius to fetch Snape, and turns to Nagini in a suspended, glittering cage.
Voldemort's comment about not caring about Draco confirms Harry's assessment that Voldemort wouldn't have cared if Harry had kept Slytherin children, since Draco is a Death Eater (and therefore, valuable on some level to Voldemort) and he doesn't even care. Hermione's pep talk to Ron shows that, in order to properly honor Fred, they need to continue fighting for what he believes in and not let themselves get trampled and die unnecessarily.
Harry, Ron, and Hermione argue about who should go to the shack. Two Death Eaters interrupt them, but Hermione turns the stairs into a slide and then conjures a wall. Harry throws the Cloak over all of them and they run through the grounds, saving Draco from a suspicious Death Eater as they go. Hermione shoots a curse at Fenrir Greyback and Professor Trelawney throws a crystal ball on his head. They see Hagrid burst in, yelling for people to stop hurting the spiders, but the spiders pick up and carry Hagrid away into the forest. A giant stops Harry from chasing Hagrid, and Grawp begins to wrestle with the giant. Out on the grounds, they find dementors and struggle to conjure Patronuses, but Luna and Seamus save them and Luna talks Harry through conjuring his own.
Luna's pep talk reminds Harry that he can call on his community in times of need—he taught them to conjure the Patronuses and now they can repay the favor and help Harry when he needs it. Saving Draco again suggests that Draco, like Wormtail, might owe Harry a favor in the future, which continues to make room for Draco to ultimately redeem himself.
Harry, Ron, and Hermione race away from another giant to the Whomping Willow. Harry briefly considers leaving Ron and Hermione, but they all squeeze into the passage. It seems smaller than they remember. They put the Cloak on as they get close to the end. They stop to listen when they can see Nagini, and they hear Voldemort and Snape. Snape offers to find Harry, but Voldemort ignores this and asks why the Elder Wand won't work for him. He says that it works like any other wand and again refuses to let Snape fetch Harry. Harry feels Voldemort's painful rage in his scar as Voldemort says that none of his wands have worked to kill Harry. He says that he needs to kill Snape in order to master the wand, and sets Nagini on Snape.
Harry's observations about things seeming smaller than they used to (the last time he was in this passageway, he was thirteen) make it clear to Harry just how much he's grown up over the course of his years at Hogwarts. He's no longer the innocent thirteen-year-old kid who ran down this passageway years ago; now, he knows that he's going to find Voldemort at the end and knows that he needs to approach with caution. Voldemort's choice to murder Snape again reinforces that he's relying on power and strength more than anything else.
Voldemort moves the cage and Nagini with him and leaves the shack. Harry pulls himself through the trapdoor and approaches Snape. Snape tells Harry to "take it," and Harry sees silver coming from his mouth and ears. Hermione conjures a flask and Harry puts the memories in it. Snape asks Harry to look at him and then dies.
That Snape is giving Harry memories calls into question whether Snape was actually the villain Harry thought he was. He clearly has something to explain, and Harry's willingness to accept this offering and effectively hear Snape out represents a turning point for both of them.