It was the middle of night, the cheers of people who celebrated Gryffindors victory could still be heard. Arth had come to the an empty classroom all alone, the windows showering him with gentle moonlight.

He took a deep breath before taking out the black book that had been on his mind the past weeks.

He opened the book, the silvery words glimmering softly as always against the black pages. However, when he put them under the moonlight sky, a couple of words began to light up.

-progression is withheld by the key. Intelligence is just a part

-those who wish to remain hidden. Twilight dark of secrets. the beginning. seek what you find but do not despair.

-backwards

-sutlucco, are you ready to carry the price?

Arth considered him an idiot. The Book of Night. He couldn't believe how he hadn't figured it out earlier. It was so blindingly obvious that he reckoned some of the readers were frustrated and willing to drop the book. Of course, there were some readers who still had no clue. No shame to them.

The first hint was that he had to read the book during night, the second hint was second over arching theme on the page. Hide and seek.

Those who want to be hidden.

The reason why nothing worked when he said the word Occultus was because he never had a desire to hide. The word might only activate during Night or while in the dark as well.

Arth closed his eyes and tried his best to desire becoming hidden. After he was sure that he had enough determination, Arth whispered the word.

"Occultus."

Arth waited for something magical to happen, yet nothing seemed to change. He even checked his book to see if something in the pages had revealed itself. There was nothing.

Was it because Arth wasn't feeling the need to hide? Did he need to force himself into a situation where he needed to hide? Arth hesitated. He had no idea if was going to even work, and if he failed, he was going to get into so much trouble.

Oh well. Curiosity killed a cat. And Arth reckoned that he would be able to weasel his way out of it by acting confunded.

Arth took out his wand and waved towards the neatly stacked desks and chairs. "I guess it's time to cause some mayhem. Wingardium Leviosa."

/—/

Filch was in his office staring endearingly at a pair of chains when he heard a loud crash. Multiple loud obnoxious crashes.

"PEEVES! YOU'VE DONE IT THIS TIME! I'LL HAVE YOUR HIDE FOR THIS! DUMBLEDORE WON'T FORGIVE YOU THIS TIME!" Yelled Filch, grabbing his keys getting ready to barge out of the windows.

He ran through the changing stairs with his beloved cat, Mrs. Norris, following behind. He had arrived at the the fourth floor when he saw what happened.

A bunch of tables and chairs somehow managed to make their way out of a classroom and fall down the stairs. They were currently repairing their broken parts and floating back up the stairs.

"PEEVES! WHERE ARE YOU! DUMBLEDORE WILL HAVE YOU FOR THIS!"

There was a pop as a transparent ghost appeared next to Filch. "It's filthy wilting Filchy! Filthy wilting Filchy! Are you angry?"

"GET DOWN HERE YOU BLOODY GHOST!"

"But why? I never did anything."

"YOU BLOODY LIAR!"

"It wasn't me. I would leave the tables here for your filthy hands to clean. These tables are cleaning themselves."

"YOU FILTHY LIAR- actually, you have a point," Filch said with his eyebrows furrowing. "Then who could it be?"

Peeves shrugged. "Student out of bed?"

Filch nodded his head. "Student out of bed."

"STUDENT OUT IF BED! STUDENT OUT OF BED!"

"COME OVER HEAR YOU FILTHY LITTLE STUDENT! YOU NAUGHTY DELINQUENT! I'LL MAKE SURE THAT YOU WILL BE RIDING THE TRAIN HOME TOMORROW!"

"But why? At least I cleaned up after my mess? Don't you think that's a bit harsh?"

Filch frowned again. "That's also a good point, most students would run rather than stay back and make sure to clean-"

Filch froze and looked around. No one was there. "Who said that? Reveal yourself!"

The only thing that responded to Filch's words were silence. Even after he glared around the perimeter, he could not find the source of the voice. He could only see a bunch of floating tables that were magically repairing themselves.

Just as Filch was about to convince himself that he was imagining things, his leg hit an invisible object. The invisible object let out grunt of pain and an audible scowl.

"Can you not go around kicking people? I'm trying to help you clean the tables and chairs you know?"

"A-Ah, sorry sir. My bad-" Filch inadvertently apologized before realizing what he was doing. "Wait a minute! You are the student aren't you! You must be using an invisibility spell!"

"Perhaps," replied the voice. Filch could now tell that the voice belonged to a young boy, most likely a first or second year student. "But then again, I might be a ghost. You should ignore me and continue to patrol somewhere else."

"A-A ghost? So you are not a student?" Asked Filch, visible confusion highlighting his face.

"Well duh, can you see me? Do I look like a student wandering out in the castle during the night? Can you even see me?"

"N-no-"

"Then do you believe that I am able to cast an invisibility charm on myself if I was a student? I'm pretty sure that invisibility charms are seventh year material."

"I-I see. But why are you invisible if you are a ghost?"

"Does a ghost need to explain why it's invisible? Now go away Filch."

Filch nodded his head before starting to walk away from the scene when he suddenly paused. "Wait a minute, there isn't a ghost that is as young as you in the ghost index! You are a student who is trying to trick me-"

"Obliviate."

Filch was blasted down the stairs as a voice sighed at him. "Damn it, I was sure that it would work."

Filch blacked out and woke up the next morning without a single account of what had happened during the night.