There is an imposter among us

By dinnertime, a new rumour had spread throughout Hogwarts; Harry Potter had struck again. Apparently, he had been caught at the scene of his newest crime, standing over the petrified body of one Justin Finch-Fletchley. He had even somehow managed to do in a ghost. How was that even possible, wondered Oleandra. How was it even remotely possible to kill that which had no life to begin with?

At any rate, the rumours also said that Potter had been called to the headmaster's office, to be expelled and sent off to Azkaban, no doubt. Oleandra stopped playing with her soup and stood to get a better view of the Gryffindor table. But there he was, the Heir of Slytherin himself in all his glory, complete with spoonful of soup in his mouth. Both ends of his table was packed with people; it seemed like people wanted to stay as far away as him as they possibly could, which made him easy to spot right there in the middle. Only his closest friends sat near him.

Since he wasn't going to be expelled, Oleandra and Daphne still needed to secure their hideout, so they grabbed a piece of bread and a chicken leg and ran off to the dungeons.

Daphne set up a simple Caterwauling Charm at the entrance, while Oleandra started painting a protective Sigil on the door. Sigils were a type of magical circle, where multiple runes were melded together, their powers fusing and cycling into each other in a positive feedback loop.

"Berkana, Elhaz, Isaz," Oleandra murmured, running her hand over the runes, who started gently glowing. "May the powers of the birch, the guardian and the brilliant combine to form an impassable wall."

Berkana glowed with a gentle white colour. The other two runes, yellow and blue-white, seemed to leap off the wall, gently merging into Berkana. Wooden stakes appeared out of nowhere and sealed the entranceway, while ice crept up and covered the entire surface. A shimmering aura condensed on its surface.

"There, that should hold," said Oleandra with satisfaction. "Unless a teacher comes around, no student should be able to get through this."

"Let's get out of here," said Daphne, holding her sides and shivering. "I hope dinner is still being served."

It was not. 

                                            _

A few days later, Oleandra boarded the Hogwarts Express along with most of the other students in school. With all that was going on at Hogwarts, with the Heir of Slytherin promising to kill every Muggle-Born in sight, nobody wanted to stay in Hogwarts longer than they should have to. All of a sudden, people who used to swear by the purity of their blood were quietly lining up to go home. 

Oleandra could count on one hand the people who had elected to stay at Hogwarts during Christmas vacation. As far as she knew, there were Potter and his two cronies, Draco, who didn't want to miss a chance to meet the real Heir of Slytherin, Crabbe and Goyle, and her sister. 

"Hold on, that's seven people," thought Oleandra, holding up seven fingers.

She sighed. Clearly attending a school that taught nothing but magic had adversely affected her arithmetic skills. But she soon brightened up; at least she would get to see her cute little sister at Christmas.

                                              _

"Merry Christmas, Daphne!" said Draco. "What did you get for Christmas? My father bought me this wonderful miniature Nimbus 2001 and its accompanying miniature Golden Snitch. The broom chases the Snitch around, see?"

The pair of miniatures were busy orbiting Draco's head. Daphne looked apprehensively at them. She certainly hoped nobody lost an eye to those things, who were whizzing around dangerously fast.

"That's very nice," lied Daphne. "My parents sent me this solid gold cauldron. It's a little heavy, though."

On paper, Daphne was returning home, and Oleandra was the one staying, in order to fool their parents. The twins had pulled a switcheroo, the oldest trick in the twins' handbook. However, Daphne was simply too lazy to keep up the charade around Draco. Since he was the only sentient being around to spend Christmas with, she had just told him the truth.

"By the way," said Draco, sniggering. "Have you read today's issue of the Daily Prophet? My father sent me this clipping, there's this hilarious article."

"Um, no, I'm afraid I haven't," said Daphne. Seriously, which child read the newspaper on Christmas Day?

"Ah, then don't read it yet," said Draco, smiling widely. "I'll go fetch Crabbe and Goyle, I'll show it to you when everyone is here." 

He frowned. 

"Those pigs, they must still be stuffing their faces in the Great Hall. Either that, or they're lost again."

A few minutes later, Draco was back with his two followers, as well as… Oleandra!?

Daphne stalked over to Oleandra and pulled her to the side.

"What in the world do you think you're doing here, dear sister?" hissed Daphne.

But she didn't leave any time for Oleandra to respond. 

 "You're supposed to be taking my place at the marriage interview tomorrow," Daphne continued. "Mother is already suspicious of us because of what happened at the Sorting Ceremony. If you show up despite having missed the train, she will start asking questions."

Of course, the Oleandra she was talking to wasn't the real one. For that matter, neither were Crabbe and Goyle. They were in fact Hermione Granger, Ronald Weasley and Harry Potter, in that order. It turned out that the reason why they had wanted Moste Potente Potions was to learn how to brew the Polyjuice Potion, which required a sample of genetic information to change one's appearance to that of another. 

And that is precisely what the trio had done. Somehow, they had convinced themselves that Malfoy was the Heir of Slytherin, or at the very least, knew who it was. And thus, they had hatched a plan to transform into his friends, in order to ask him directly. 

The day Hermione had gone to borrow the book, she got into a physical altercation with Daphne, so she had taken the chance to tear out a few handfuls of Daphne's long silky hair, which she had kept in prevision for her plan. As for Harry and Ron's needs, they had knocked out the real Crabbe and Goyle with poisoned cupcakes.

Incidentally, the Polyjuice Potion made with Daphne's hair had the breath-freshening properties of spearmint. How very cool.