After Arthur calmed down, they decided to get out of bathroom and go back to the common room when a loud voice made all four of them jump.

"RON!"

Percy Weasley had stopped dead at the head of the stairs, prefect badge agleam, an expression of complete shock on his face.

"That's a girls' bathroom!" he gasped. "What were you —?"

"Just having a look around," Ron shrugged. "Clues, you know —"

Percy swelled in a manner that reminded Arth of a a very toad.

"Get — away — from — there —" Perry said, striding toward them and starting to bustle them along, flapping his arms. "Don't you care what this looks like? Coming back here while everyone's at dinner —"

"Why shouldn't we be here?" said Ron hotly, stopping short and glaring at Percy. "Listen, we never laid a finger on that cat!"

"I know," said Percy fiercely, "butdo you think the others will think the same way if they saw you? Your reputation would drop and you might even get in trouble!"

"You don't care about me," said Ron, whose ears were now reddening. "You're just worried I'm going to mess up your chances of being Head Boy —"

"Five points from Gryffindor!" Percy said tersely, fingering his prefect badge. "And I hope it teaches you a lesson! No more detective work, or I'll write to Mum!"

And he strode off, the back of his neck as red as Ron's ears. Arth waited for Percy to dissipate at before speaking.

"I mean, we were in a girls bathroom. He does have a reason to be angry."

"Shut up Arth, if it's because of the song I said earlier, I already said I'm sorry?"

"What do you mean? What song? I'm just worried for you my friend. I don't want your family relationships to sour."

"... you sarcastic little-"

"Ooh. No naughty words my friend. This is a learning facility."

"..."

When they arrived at the common room, Ron was still in a very bad temper and kept blotting his Charms homework. When he reached absently for his wand to remove the smudges, it ignited the parchment. Fuming almost as much as his homework, Ron slammed The Standard Book of Spells, Grade 2 shut.

"Wow, let me help you with that," said Arth. He un-ignited the paper and restored it to top top condition.

"...thanks."

"No biggie. You really shouldn't cast spells when you are emotionally out of hand. Things can get... fiery."

Hermione sighed before she closed her book with a slam.

"Who can it be, though?" she said in a quiet voice, as though continuing a conversation they had just been having. "Who'd want to frighten all the Squibs and Muggle-borns out of Hogwart's?"

"Let's think," said Ron in mock puzzlement. "Who do we know who thinks Muggle-borns are scum?"

He looked at Hermione. Hermione looked back, unconvinced.

"If you're talking about Malfoy —"

"Of course I am!" said Ron. "You heard him — 'You'll be next, Mudbloods!'— come on, you've only got to look at his foul rat face to know it's him —"

"Malfoy, the Heir of Slytherin?" said Hermione skeptically.

"Look at his family," said Harry, closing his books, too. "The whole lot of them have been in Slytherin; he's always boasting about it. They could easily be Slytherin's descendants. His father's definitely evil enough."

"They could've had the key to the Chamber of Secrets for centuries!" said Ron. "Handing it down, father to son..."

"Well," said Hermione cautiously, "I suppose it's possible..."

"I find it highly improbable, he ain't got the brains not the will to do it and keep it a secret if he did." Said Arth, not looking up from his book.

Harry snorted.

"You're right, how could it be Malfoy? Who do you think it is Arth?"

"Well, if it isn't just a prank and there is an actual heir of slytherin, it's either going to be a person who doesn't go to the school or a person who isn't a slytherin."

"What?" Said all three of them with a confused look.

Hermione habitually raised her hand.

"Why would it be like that? Wouldn't you suspect slytherins the most?"

Arth sighed and put down his book.

"That's exactly why I don't think it's a person from slytherin. It's too obvious. Chamber of secrets that can only be opened by "Slytherin's heir". Kind of an automatic assumptions won't you think? Something that would find blatantly obvious to the point you would be stupid if you didn't consider it."

(AN: This bugged me a lot in the original novels. Like why did everyone suspect Harry of the attacks when he was in Gryffindor? No one knew he was a parseltongue at that time yet still everyone thought it was him? Just because he found Mrs. Norris first. And yeah Hermione and Ron who were there were totally accomplices. That's it :) bye)

"So... are you saying that you are stupid?" Said Ron with a dumb look on his face.

"I'm saying that the heir of slytherin would be an idiot to open the chamber if he is a slytherin."

"...but don't you have to be the Heir in order to open it? How would it work?"

Arth rolled his eyes.

"If its a secret word or a hidden button, then all the heir has to do is control someone to open it. Then, even when the person gets caught, the real culprit is still on the loose."

"You... you fucking genius."