Oleandra landed in front of the painting of Barnabas the Barmy on the seventh floor of the castle, and tried to remember Ginny's instructions to make the Room of Requirements manifest itself.
'I need to see the Gate,' Oleandra mentally repeated to herself, pacing in front of the painting back and forth. 'I need to see the Gate.'
After a few moments, the outlines of a doorway drew themselves on the wall opposing the painting; and half an instant later, a doorknob popped out of the rectangular shape that had just appeared. Finally!
Oleandra grasped the doorknob and slammed the door open, walking through the doorway and into a nearly empty room: just as she had wished, the Gate to Nidavellir was inside. She walked up to it and ran her fingers over the intricate runes that covered it… and her heart sank: the Gate was cool to the touch; whoever or whatever had come through here, it had not been a recent affair.
A cursory look around the room with her Mystic Eyes informed her that there was nothing more to learn here; her search would have to continue elsewhere, and she knew exactly where to look. Only four people could open the gate; those who had been marked with the runes of the stars: Herself, Daphne, Tracey… and Draco.
Taking out her pocket watch, Oleandra noticed that she had somehow completely missed lunchtime and the first half hour of History of Magic while running around the school. She needed to calm down and eat something; it wouldn't do if she fainted during Professor Snape's antidotes exam, which was the following period. Oleandra retrieved a stale pastry from her pouch and began munching on it while thinking.
The Earth had not known any Dusk-Elf incursions in thousands of years, so surely the Pale Blue Dot was concealed from their sight, just like their world, Svartalfheim, was concealed from hers. If neither side could breach the other's concealment, then if a Dusk-Elf had made it to Earth, then that must surely mean that the fault lied on Earth's side. Which meant that: Oleandra had three objectives: apologize to Harry, apologize to Daphne, and interrogate Draco, the most likely culprit.
Oh, and four: maybe ask someone to the Yule Ball; talk about having a full dance card!
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Never before had Oleandra had so much trouble in Potion's class; not only did she have to keep an eye on her ingredients, she had to make sure that Neville did his tasks correctly! And with the threat of being poisoned looming over their heads, the poor boy was about to have a panic attack. Professor Snape had mentioned multiple times over the year that he would be poisoning a random (read: Harry) student for them to test out their antidotes.
Oleandra was fairly certain that Professor Snape wasn't allowed to poison anyone, but the man had tenure for some reason; he couldn't be fired, and he could always say: "Oops, I guess my hand must have just… slipped." At any rate, Oleandra couldn't imagine a worst time to be incapacitated, so she had to keep an eye on Neville's part.
Eventually, the class ended with nobody keeling over; it seemed that Professor Snape had been making empty threats this entire time. Oleandra and Neville barely scraped by through some miracle, their antidote being passable.
Just as Oleandra was trying to figure out which one of her objectives to complete first, one of them just presented itself before her. It just so happened that the boys of the Gryffindor Golden Trio were looking for a dance partner to ask to the Yule Ball, and Oleandra fit the description perfectly: not surrounded by other girls (it was too embarrassing to ask a girl out in front of a gaggle of her friends), pretty (this one goes without saying) and… were there any other criteria when considering eligibility? Probably not, right?
"I dunno," Harry was saying as he exited the classroom. "I was thinking of asking Cho out…"
"At this rate," moaned Ron, "we're going to have to go alone. There's no way I'm asking Eloise Midgen…"
His voice trailed off as he spotted Oleandra, who was still deep in reflection, and he started discussing something with Harry in a low voice. Recognizing their voices, Oleandra turned around to face them; oh, and of course, Hermione was there too.
"Er— Harry, do you have a moment?" said Oleandra, awkwardly. Might as well get it over with.
"Yeah?"
"I just wanted to apologize," Oleandra said. "For… you know, that thing at the Three Broomsticks— I knew you were invisible, and I did something mean to you…"
"What thing?" asked Harry, slightly confused. "Oh, that. I'd already forgotten about it, it's fine."
An idea suddenly popped into her head.
"I still wanted to apologize," Oleandra said. "By the way, have you solved your clue? If you'd like, I could give you a hint—"
"Harry will solve it by himself," said Hermione firmly. "Won't he?"
"Right…" said Harry glumly.
"All right, then," said Oleandra. "It's just that I thought I had an unfair advantage, since our common room is right next to… well, you know."
Harry and Ron didn't know, but Hermione knew everything there was to know about it. She constantly liked to remind people how she had read Hogwarts: A History. Good thing Harry had her to help hold his hand!
"Oleandra, you're a girl, right?" said Ron, seemingly out of nowhere.
"I…er— yes?" said Oleandra, who was now totally at a loss as to what they were talking about.
"W-would… would you like to go to the ball with Harry, o-or me?" he said, stuttering a little, his face turning tomato red. "If you don't already have a partner," he added quickly.
"Hmm…" Oleandra considered her options. If she picked Harry, then Ginny would probably tear her head off. As for Ron… everyone in Slytherin hated the Weasleys, considering them blood traitors. It would certainly be very funny to take him as her partner, if only to annoy them. And Ron's looks weren't bad by any means…
"Fine," said Oleandra. "I'll go with you then, Ron."
Ron and Hermione both looked at her in surprise, as if to say, are you really, really sure?