At the customer service counter, Hermione asks to be admitted to Bellatrix’s vault, and a goblin asks her for identification. When the goblin says her wand will suffice, Harry realizes that they must know Bellatrix lost her wand and must be expecting an impostor, so he uses the Imperius curse to control the goblin’s mind. The goblin compliments her on her new wand, which makes Travers suspicious, so Harry controls him as well.
The entire party, led by the mind-controlled goblin, gets into a rail cart and travels deep into the vaults. Harry curses himself for the strategy they’ve adopted, realizing that the Death Eaters know all about who stole Bellatrix’s wand, and that posing as Bellatrix has already brought them too much scrutiny and attention. When the cart passes through a waterfall and all of their Disguising spells are undone, Griphook tells them that the Gringotts employees have set up defenses indicating that they know impostors are present.
A dragon blocks the passageway to the vault, but Griphook shakes metal instruments called Clankers, which the dragon has been trained to fear, and it backs up. The mind-controlled goblin places his palm to the door of the vault, and it opens.
Harry knows from his conversations with Dumbledore that if a Horcrux is in the vault, it must either be the Hufflepuff cup or else an unknown object, so they have no choice but to look for the cup. Unfortunately, whenever they touch anything inside the vault, it burns them and then multiplies into myriad worthless copies, so that if they continue touching items in the vault, it will eventually fill and crush them. They try not to touch anything as they search, but this proves impossible.
Finally, they see the cup sitting high up out of reach. The dragon roars outside the door, and the heat from the multiplied treasure is overwhelming. Hermione Levitates Harry toward the cup, but he knocks over a suit of armor, and they begin to be buried in hot objects. Harry uses the sword to skewer the cup through a handle as Griphook sinks beneath the burning treasure. Harry stops to save him, letting go of the sword, and Griphook seizes the sword, flinging the cup into the air. Harry realizes that Griphook never believed Harry would keep his word, but he manages to catch the cup again as Griphook disappears.
A crowd of goblins appears in the passage, there to apprehend Harry and company. Harry uses his wand to free the chained dragon, then the three get on the dragon’s back and ride it through the tunnel, eventually emerging in the bank lobby, exiting through the door, and flying off into the sky above Diagon Alley.