"Oh," Tracey said as she opened the door. "It's you three again."
"Who is it?" Oleandra voice echoed from the kitchen.
Oleandra was attempting to bring the water in a kettle to the boil using nothing but her own innate abilities; unfortunately, it seemed heating water did not fall within the purview of her Authority. Unless something had gone dreadfully wrong, lakes weren't meant to be boiling, after all.
"It's us," Harry Potter called from the vestibule. "We need to talk. It's urgent."
The kettle gave a shrill whistle as Oleandra tapped it with her wand. She then gave her wand a small wave, and the kettle wobbled skywards above the waiting teapot, in which she'd already placed the leaves, and with another flick, the kettle tipped over, spilling piping hot water everywhere but into the teapot.
"Let them in!"
Cursing under her breath, Oleandra caught the kettle by its handle and manually redirected the stream of scalding water. Personally, she blamed Dolohov's wand for the mishap; it clearly wasn't suited to the delicate, precise art of household spells and lifestyle magic. Yes, she thought to herself rather smugly, it was an excellent thing she had decided to test this before Charming the tea set to autonomously serve her guests.
This utter lack of control couldn't possibly have been due to her lack of practice, perish the thought. That, at least, was Oleandra's reasoning as she bustled out of the kitchen, balancing a platter burdened with a bottle of milk, the teapot, and several mismatched mugs to find Tracey and the four Gryffindors in the sitting room, locked in a silent standoff.
"I suppose you wanted to hear what the rest of Dumbledore's diary had to say?" Oleandra asked, inviting her guests to sit with a wave of her hand. "Or is this perhaps about…?"
"Tracey," Harry said hesitantly, as he and his friends lowered themselves onto a divan, while Oleandra and Tracey took their seats in front of them. "Could you give us a moment?"
"No more secrets," Tracey said rather unkindly.
Oleandra sighed. This was one secret she didn't at all mind sharing, but before addressing Harry's concern, the tea had steeped long enough; it was time to serve her guests.
"Yes, I'm aware that Hufflepuff's cup is a Horcrux," she said, pouring tea into each of the six cups. "There's the milk, help yourselves," she added, pointing at the bottle. "Though it might be a little thin. Apparently, the Sanctuary only has the one, overworked cow."
According to Gamp's Law of Elemental Transfiguration— a principle Ron had come to know rather too well in recent months, much to his dismay— proper food could not be conjured out of thin air.
However, drinks such as milk fell outside that restriction; the trouble was that any magically produced milk lacked all real nourishment. This was why one particularly enterprising Wizard in the Sanctuary had imported a cow and begun multiplying its milk by magic, selling the results back to the locals.
"No sugar?" said Ron, giving his tea a cautious sniff. He took a sip, his face scrunching up at the bitterness. It was nothing like the tea his mum made.
"Maybe if you'd paid attention in Transfiguration," Tracey said caustically, "you'd remember the Sweetening Spell's incantation."
Having been harassed by Harry's friends at school over the past few months, she was none too pleased to have the man himself in her home.
"Why don't we get straight to the point?" said Hermione quickly. "Dumbledore left us to deal with the Horcruxes, so we'd like you to hand over Hufflepuff's cup."
"Just like that?" Oleandra said, taking a sip of tea.
"Er… well, yes," Hermione said, puzzled.
"She wants something in exchange," Sirius deduced. "Am I right?"
Oleandra nodded, but Tracey just looked confused. What in the world was a Horcrux?
"Don't you want to see Voldemort dead?" said Harry, incredulous. "We have to destroy the Horcruxes, or he'll just keep coming back. Now's the best time to do it, while his body's gone!"
"Hang on, hang on!" Tracey cried. "What do you mean, he'll just keep coming back!? I thought Oleandra killed him! And what's a Horcrux!?"
Oleandra quickly filled her in.
Voldemort had split his soul apart and stored the pieces in vessels called Horcruxes, and the attractive force they generated prevented his spirit from being drawn into the Door of Life and Death… that is, the Archway in the Department of Mysteries, whose true identity was the Gateway to Niflheim, the World of Mists.
"First of all, do you even have a way to destroy the Horcruxes?" Oleandra asked. "From what I understand, they're protected by very powerful magic."
"Not yet," said Harry grudgingly. "We thought we might use Gryffindor's sword— it's Goblin silver, so it should have absorbed the basilisk venom back then. That ought to be enough to get past the protective enchantments… but the sword's in Hogwarts, according to Ron. Ginny's got it… and she's a Horcrux too."
Neither Harry nor his friends were nearly powerful enough to destroy a Horcrux by magic alone, so they were forced to depend on other, more external means.
"Hang on," said Oleandra slowly, tapping her teacup rhythmically as she thought. "Daphne's a Horcrux, and Voldemort's made her impervious to harm— physical or magical. But Ginny's a Horcrux as well, and she's still perfectly vulnerable, I'm sure of it… I wonder why that is?"
The Gryffindor Trio and Sirius shared a knowing glance.
"In any case, I still have use for Hufflepuff's cup, so I don't intend to hand it over until the other Horcruxes are destroyed," said Oleandra firmly. "And unlike you lot, I actually have the means to destroy them, so I think it would be for the best if the cup stayed with me."
"Are you having a laugh!?" Ron blurted out. "If you've got a way to destroy the cup, then why haven't you done it already?"
It was now perfectly clear to Harry and Hermione that Oleandra had already been compromised. They were still convinced she was a Horcrux— Harry's vision of Daphne and Oleandra speaking in Parseltongue had been more than enough evidence. As they saw it, Oleandra had accidentally absorbed a fragment of Voldemort's soul, and it was clouding her judgment, which, of course, explained why she seemed so reluctant to destroy the cup… even though she had already killed Voldemort himself.
However, now was not the time to confront Oleandra, so Hermione quickly decided to change the subject.
"You've found a way to destroy the Horcruxes?" said Hermione, her curiosity piqued. "Could you— show us?"