Paying a visit to the Gryffindor common room

"All right, false alarm," Oleandra told Daphne as they exited the Defense Against the Dark Arts classroom.

"Is exactly what the stranger who has taken over my sister's body would say, to make me lower my guard," said Daphne in a serious tone, squinting suspiciously at her twin.

"…"

"I'm only joking," Daphne said, cracking a smile. "I can tell you're still you. Can you tell me what's going on, now?"

"If you keep this up, it'll be me doubting whether you're still Daphne in there," Oleandra said. "Since when do you like to joke like this, Little Miss Prim and Proper?

"Maybe you're rubbing off a little on me," admitted Daphne. "When we were kids, you used to be so gloomy. But answer my question, what in the world is going on with that book?"

"I thought this thing was a dark magic item," said Oleandra, waggling Tom Riddle's diary. "But it's in fact some Gryffindor kid's imaginary friend, so I'm returning it. Because I'm a good person, see?"

"Now I'm certain something's definitely wrong with you," joked Daphne.

"Don't you want to get back at Granger?" asked Oleandra. "We can sneak into the Gryffindor common room and leave the diary there like it asked, and at the same time we could prank Granger in her sleep."

Daphne's eyes glinted. Under her icy-cold and forbidding demeanour, she was just as vengeful as her sister was!

                                          _

Just before dessert was served, the two sisters sneaked out of the Great Hall. Daphne looked back regretfully; her favourite dessert was being served: key lime pie. Nevertheless, she swallowed back her saliva and soldiered on.

Just outside the Great Hall, Daphne took out a pocket mirror and was busied herself drawing Perthro in its reversed form. She pictured Neville Longbottom; her form shimmered and twisted, and in her place stood an unremarkable, chubby boy.

"Your gaze is too focused," Oleandra whispered to her. "Try to look as lost as you possibly can, and stop scowling."

Daphne nodded, and she hid herself behind a pillar. Oleandra turned back and prepared to reenter the Great Hall. "Remember not to let anyone touch you, it's only an illusion," she said before slipping back inside.

As she passed through the double doors, she noticed a pair of eyes following her. Oleandra briskly walked back to her seat and dug into a slice of pie, pretending she hadn't noticed Professor McGonagall's stare. This was bad. The last thing she needed was the Gryffindor House's Head to pay attention to her just before she was about to mess with her House!

A dozen minutes later, supper was officially over, and the students of the four Houses streamed towards the exits, back to their respective common rooms. Oleandra erased her presence, and discreetly followed the real Longbottom into the men's bathroom. 

"Isaz, Dagaz," she whispered into his back. "Time lock."

                                          _

"Who said that?" cried Longbottom fearfully, whirling around, but nobody was there; he was alone in the toilet. The only sound to be heard was the woosh of water gushing from the tap. With a sigh of relief, he turned back to the sink and continued washing his hands. 

Neville frowned, was it just him, or did the water go down the drain abnormally fast? He leaned in for a closer look; the flow of water was normal. It seemed his mind was playing tricks on him. He had been rather on edge lately. Everyone knew he was nearly a Squib, and as such he was deathly afraid that Slytherin's creature would come after him. 

Neville squinted his eyes as he looked out the window while drying his hands, as the sun was shining brightly. And then, it hit him. Why on earth was he watching the sunrise right after suppertime!?

                                           _

Oleandra watched as Longbottom's movements gradually slowed down, then finally stopped. If she kept up the spell and waited long enough, she could put an unresisting target of his level in stasis after a few minutes. With the amount of magic she could mobilize by herself, it would take years for her to stop an adult dragon's time!

Her job done; she composed a simple Galdr to communicate with her sister at a distance.

"Ansuz, Wunjo," she chanted. "By the powers of the Æsir and the Standard, I open a channel of communication with my twin."

Odin's discovery of runes represented more than the discovery of a new branch of magic, it also represented a whole new method of communication. As such, one could use Ansuz to communicate with others. Its power could even reach other worlds when paired with Uruz, the crossroads and the gateway between worlds!

"Oleandra speaking. Longbottom's down for the count. I'll be waiting for your signal in the Grand Staircase. Be on the lookout for McGonagall. See you later."

"I'm inside. Their common room is behind the Fat Lady's painting. The password is Frivolous Frisbees. I'll open the door at one o'clock in case the Fat Lady's gone to sleep. Don't get caught."

                                              _

A few hours later, just as Oleandra was beginning to doze off, the portrait of the Fat Lady swung open. 

"You're late," said Oleandra, yawning. "Did you fall asleep in Longbottom's bed or something?"

"Sorry, his bunkmates were playing Exploding Snap until two in the morning. I had to make sure they were asleep after that, too."

Oleandra looked around curiously as the Gryffindor common room. Flames flickered in the fireplace, creating oscillating shadows where the light of the fire hit the furniture. Everywhere she looked, there was red and gold. Tapestries covered the walls, and a nice carpet covered the ground. Too bad the décor would be changing after they were done with it!

The diary didn't mention where exactly she should leave it, so Oleandra just lifted an abandoned teacup and placed the book under it.

"There, all better," she said. "Don't they know leaving something wet on wood will stain it?"

"Whatever," said Daphne, waving her hand. "I'll leave the rooms to you. Stairs to the left lead to the boys' dormitories; right to the girls'. I'll take care of the common room."

Oleandra's presence vanished, and she tiptoed up the stairs to the boys' dorms first. Luckily, each room's occupants were listed on a plaque at the doorway. She quickly found that Potter and Weasley shared a single room; this was too easy! She peeked inside; everyone seemed sound asleep. Oleandra walked up to each of its occupants' beds and carved Hagal on their bedposts, somewhere difficult to spot.

As she walked down the stairs, she saw Daphne hard at work turning the red to green and the gold to silver. Oleandra gave her a silent thumbs up, before repeating the same process in Granger's room. When she returned to the common room this time, she saw Daphne inscribing a sentence on the walls.

"Snakes rule – Potter," she read out loud. "Is that the best you could come up with?"

Daphne's face reddened.

"Actually, don't even answer that," said Oleandra. "I'm going to activate Hagal, so get ready to run."

"Hagal!" bellowed Oleandra. "I call upon the first of winters at the end of time, cast my foes into an icy tomb. Fimbulvetr!"

"RUN!"