That's an intriguing exchange. What exactly has Hagrid talking in the same sort of indirection that he uses for the man who killed her parents?

The goblin peers down at Sarah suspiciously but doesn't comment. "I will have someone take you down to both vaults. Griphook!"

Griphook is, apparently, yet another goblin. Hagrid follows him to a door, and he holds it open for them. On the other side, there is a narrow stone passageway lit with flaming torches. It slopes steeply downward and there are little railway tracks on the floor. Griphook whistles and a small cart comes hurtling up the tracks toward them. Hagrid climbs in with some difficulty.

Sarah climbs in too.

They're off.

At first they just hurtle through a maze of twisting passages. Left, right, right, left, middle fork, right, left, it soon becomes untenable to keep track of the path. The rattling cart seems to know its own way, because Griphook isn't steering.

Cold air rushes past them, and at one point there's something that looks a lot like a burst of fire at the end of a passage but they plunge deeper too fast for much more detail to be made out. They pass an underground lake where huge stalactites and stalagmites grow from the ceiling and floor.

When the cart stops at last beside a small door in the passage wall, Hagrid gets out and has to lean against the wall to stop his knees from trembling. He's looking positively green.

Sapphire tries to give a sympathetic look to Hagrid but she's smiling too hard. That was fun.

Griphook unlocks the door. A lot of green smoke comes billowing out, and as it clears, Sarah can see the vault's contents: mounds of gold coins, columns of silver, heaps of little bronze Knuts.

"All yours," smiles Hagrid. 

"Is there anything that says how much there is here?"

"Don' think so, but more'n enough."

"How much do you think I'll need for the supplies on the list?"

"Ah, we'll get some fer a couple o' terms and change so yeh can buy stuff yeh like." He starts grabbing some gold and silver and bronze and putting it into a bag, not caring much to count. "The gold ones are Galleons," he explains. "Seventeen silver Sickles to a Galleon and twenty-nine Knuts to a Sickle, it's easy enough."

That sounds like the exact opposite of easy. Why would you use prime numbers for conversion? "If you say so."

He turns to Griphook. "Vault seven hundred and thirteen now, please, and can we go more slowly?"

"One speed only," says the goblin.

They board, and the cart starts again. They go even deeper now and gather speed. The air becomes colder and colder as they hurtle round tight corners. They go rattling over an underground ravine, deep enough the bottom's out of sight.

Sarah enjoys this ride too.

They soon reach vault seven hundred and thirteen... which has no keyhole.

"Stand back," says Griphook importantly. He strokes the door gently with one of his long fingers and it simply melts away. "If anyone but a Gringotts goblin tried that, they'd be sucked through the door and trapped in there," the goblin says.

Sarah takes a couple steps backwards.

Griphook stands out of the way, and inside of the vault there is...

Nothing.

Or, wait, there's a grubby little package wrapped up in brown paper lying on the floor, there. Hagrid picks it up and tucks it deep inside his coat.

"Come on, back in this infernal cart," says the giant.

Well that doesn't make this less intriguing.

One wild cart ride later they stand in the sunlight outside Gringotts.

"Might as well get yer uniform," says Hagrid, nodding toward Madam Malkin's Robes for All Occasions. "Listen, Sarah, would yeh mind if I slipped off fer a pick-me-up in the Leaky Cauldron? I hate them Gringotts carts." He does still look a bit green around the gills.

"Sure, I think I can handle getting clothes myself."

"Thanks."

Off he goes.

Sarah walks into the store.

Madam Malkin is a squat, smiling witch dressed all in mauve.

"Hogwarts, dear?" she says as soon as she spots Sarah. "Got the lot here—a young man being fitted up just now, in fact."

In the back of the shop, a boy with a pale, pointed face is standing on a footstool while a second witch pins up his long black robes.

"Yes, do you sell more casual wear as well?"

She stands Sarah on a stool next to the boy, slips a long robe over her head, and begins to pin it to the right length. "Absolutely, but after I'm done with this."

"Hello," says the boy. "Hogwarts, too?"

"Thank you." She says to Madam Malkin. Then she turns to the boy. "Yes. I'm excited."