SCOTLAND, MCGONAGALLS CLASSROOM. 

"That's wand needs replacing mr Weasley,"  McGonagall announced as the room echoed with chuckles from Rons pet, Scabbers transfiguring into a furry water goblet and the tail still wiggling. The professor walked away, her green velvet robe draping behind her as Hermiones hand shot up. Y/n sat behind her and held her 13 and 3/4 inch wand in her hands, tracing her finger against the patterns. "Yes miss granger?" She asked and stopped in her tracks.

"Professor, I was wondering if you could tell us about...the chamber of secrets," she asked, the room suddenly fell silent, y/n's and most other people's head looked up as Hermione mentioned the name. McGonagall scanned the expressions of her students in the classroom before speaking up again.

"Very well, you all know of course hogwarts was founded over a thousand years ago by four greatest wizards and witches of the age, Godric Gryffindor, Helga Hufflepuff, Rowena Ravenclaw and Salazar Slytherin," she paused walking past a couple ravenclaws who sat by each other. "Now three of the founders coexisted quite harmoniously, one did not," she again paused, fiddling with her wand.

"three guesses who," y/n heard Ron whisper to her brother.

"Salazar Slytherin wished to be more selective about the students admitted hogwarts, he believed magical learning should be kept in all magic families, in other words pure blood," she told the students, everyone almost hanging off the edge of their seats, so interested in the story. "Unable to persuade the others he decided to leave the school, now according to legend Slytherin had built a hidden chamber in this castle, known as The Chamber of Secrets though shortly before departing he sealed it until another time his own true heir returned to the school, the heir alone would be able to open the chamber and unleash the horror within and by so doing purge the school of all those who in slytheins few were unworthy to study magic," she finished and adjusted her tiny glasses at the edge of her nose, y/n immediately turned to hermione understanding what Mcgonagall had meant.

"Muggle-borns," Hermione pipped up.

"Well naturally the school had been searched many times, no such chamber has been found," she finished and began to stride up to her desk again.

"Professor, what exactly does legend tell us what lies within the chamber?" Hermione asked.

"The chamber is said to hold the only thing the heir of slytherin can control, it is said to be the home of a monster," McGonagall said, Ron and y/n both turned to Malfoy who was smirking at the two.

-

It was the night after a collective amount of months of Hermione and y/n gathering the ingredients for a polyjuice potion, it was the Christmas holidays and not too long ago did Harry find out he could speak parseltounge, a language that was able to speak to snakes and was also rare across the entire wizarding world, this caused excessive amounts of rumours about the twins being the heir of Slytherin, even though y/n knew she didn't understand what either Harry or the snake was saying in the charms club the four friends had attended to.

Even with all the rumours for the twins being the heir of slytherin, the four had another suspect for the petrification of Mrs. Norris. Naturally they guessed Malfoy was the caultprate seeing as he too, among many other Slytherins despised muggle-borns. So naturally the four decided to come up with the plan to use polyjuice potion for all for to sneak inside the Skytherin common room and figure out if Draco Malfoy really is to blame..

Y/n sat with Hermione in the girls lavatory, Ron and Harry were out on a mission, to pluck Crabbe and Goyle's hairs and make them unconscious, Hermione had already pulled off Millicent Bulstrodes hair but y/n hadn't picked any, the potion would have a terribly negative on the drinker if they were ill, so y/n was forced to not partake in this little mission, which did disappoint the three others. Hermione stirred the pot once more before letting go of the handle and grabbed a folded set of Slytherin robes.

"Keep an eye of the potion whilst I get dressed, I won't be long, make sure it doesn't throth around the cauldron," she told her, y/n nodded, sniffing and wiping her nose with a tissue. Hermione went into a stall and dressed unbelievably quick, chucking her folded Gryffindor robes on the ground next to her.

"Didn't throth," y/n told Hermione as she examined the cauldron and nodded, she lifted up the spoon, both the girls upper lip folded at the clotted green goo. "Grim," she said, hermione nodded in response.

"Lucky you're not swallowing it," Hermione said and put the spoon back into the pot.

"Can you even swallow it?" y/n joked, hermione let out a small giggle.

"I'm not so sure," she said and stirred it once again. "Most probably," she said and y/n sniffed, her knees pointed up to the ceiling as she remained in her robes, even wearing hermione Gryffindor robe because she was cold in the large bathroom. Four loud footsteps and panting ran inside the room and stopped infront of Hermione and on y/n's right. "Well did you get the hairs," she questioned the boys, both held out their right arm to show the two different hair colours.

"What are those?" Ron questioned, seeing the neatly folded Slytherin robes beside hermione.

"Slytherin robes me and y/n had to sneak them from the laundry," Hermione told them and pulled up the slimy goo.

"We going to drink that?" Harry asked as hermione hummed in responses staring at the potion.

"We have exactly one hour until we turn back into ourselves," she told the boys as they exchanged a disgusted look.

Hermione got up and pulled the cauldron over to the sinks behind to her, she grabbed three glasses and poured the substance into all three cups, y/n got up and walked over to the sinks, sitting on the edge of one, watching the rest drink the potion.

"Yummy," y/n commented as the three all looked at her disturbed. Hermione filled half a glass full, frowning at the filthy goo.

"Cheers," hermione spoke sarcastically and they clashed their glasses together, y/n watched happily as they all swallowed down the thick juice down their throats. Y/n watched as all their lips left the glass and their expressions were full of distaste.

"I think I'm going to be sick," Ron announced, dropping the glass and running to the stalls. Hermione gagged before dropping the drink too.

"Me too," she said and ran to the stall. Y/n sat there unable to do anything and watched neither gag and drop his glass. His hands on the sink.

y/n followed his eye sight and watched as bubbles popped up from underneath his skin. "Is that supposed to happen?" She asked and Harry shrugged, he looked into the mirror watching the same effect continue, merging from Harry's face to Goyles. The two turned around when they heard a stall unlock and saw Crabbe exit.

"Ron?" They both asked, he looked up and saw Harry who was now Goyle shocked.

"Harry," he said, y/n looked at the two who were still the same people just with another appearance. "Bloody hell," Ron told with a small smile.

"You need to sound more like crabbe," Y/n told him and he cleared his throat.

"Bloody hell," he repeated. The twins nodded.

"Hermione you coming?" Harry called at the locked stall.

"Just go, your wasting time!" She yelled back.

"Hermione are you okay?" Harry asked and y/n slowly walked over to the stall she was in.

"Just go! I'm fine!" She yelled and y/n looked at the two.

"Go on, I'll take care of her," y/n told them as the two looked at each other before sprinting out of the toilets and y/n knocked on the stall, hermione slowly unlocked it. Y/n gasped at what she saw.

"I look hideous don't I," she said and y/n formed her lips into a line.

"I wouldn't say hideous, but quite...different," she said and looked at the ginger fur that traced along hermiones skin, furry cat ears poked above her bushy hair and a tail tore apart the back of her skirt, her small brown eyes had morphed into a toxic yellow glaring down at y/n.

"I plucked off cat hair not Millicent's," she said and stood up turning around showing the tail that stuck out from behind.

"I can see that Mione," she giggled and shook her head.

-

The two boys came running in again, hermione had been crying at the appearance of her ever since they had left, y/n stood back, and wiped the tears into the ginger fur that rested on Hermione cheeks.

"That was close," Ron explained, y/n walked over to the stall door ready to unlock it.

"Hermione, come out, we've got loads tell you," Harry told her, panting. Hermione sighed loudly.

"go away!" She bellowed and y/n stood outside of the stalls, seeing the boys were now to their original state although Harry didn't have his glasses hooked onto his nose.

"Wait until you see it, it's awful," moaning myrtle told the two boys as y/n stood in the doorway and the ghost floated away, giggling.

"You might want to listen to myrtle for once in your life," y/n told the boys as she stood aside and opened the door, Harry fiddled with his rounded glasses and his eyes later widened.

"Do you remember me telling you that polyjuice potion was only for human transformations?" She started and began to turn her body. "It was cats hair I pulled off Millicent's bulstrode robes," hermione paused and turned her face towards the boys, her eyes gleaming with yellow in the moonlight. "Look at my face, I'm hideous," she said and shook her head.

"Look at your tail," Ron added with a grin, y/n began to giggle and she also shook her head, Moaning myrtles horrid giggles went through one ear and out the other.

Harry turned his head slightly, recognising a leather back book laying on the wet floor, soaking in the water. He walked over to go grab it and watched as the water dripped off the corner of the book. Y/n walked over next to him and held it too, she traced her finger over the letters.

"Tom Marvolo Riddle," she said quietly to her brother as they shared a confused look.