Site-41: Antimemetics Division Headquarters
Elise Dunwall looked at the window on the right side of her screen.

…The "sum" of the symbols is equal to a previously unknown integer (designated Theta Prime by Prof. Hutchinson) of intermediate value between 5 and 6.

She then looks at the list open in the window on the left side of the screen.

SCP-001 Awaiting De-classification [Blocked]
SCP-002
SCP-003
SCP-004
SCP-005
SCP-006
SCP-007
SCP-008
SCP-009

She turns to her assistant.
"Do you have the timer ready, Liz?"
"Yes ma'am," the younger woman replies, "Two-thousand five-hundred and sixty seconds."
Elise opens the search function on the left window and types in the address.
SCP-SCP-033
Enter
The start button on the timer makes a faint clicking noise as it is pressed.
Page not found.
"Reset the timer."
"Yes ma'am."
SCP-[SCP-033]
Enter
Click.
Page not found.
…
Elise leans back in her seat and lets a sigh escape.
"It was a good hypothesis."
She chuckles a bit. "Yes, but being a good idea doesn't mean that it was right. 'The Missing File Number.' Heh. Seems a bit silly now that I think about it. There's still one thing that doesn't quite line up though…"
"Something that you can't put your finger on?"
"No, nothing like that. It's just that all the secondary documentation I read about oh thirty-three would indicate that, in order to activate the effects, the number or symbol would need to represent the value to the person writing it down. If someone did fill in this hypothetical slot, they would have to have picked something which could clearly represent oh thirty-three. The file number would make the most sense to represent it as long as we're not having someone create a custom character, and doing that would probably break all of our systems."
"Maybe math's just being picky and is attributing the file number to the file itself."
"Hmm."
Elise continues to skim the document, looking for something she might have missed.
"Wait a second."

(designated Theta Prime by Prof. Hutchinson)

"Liz, reset that timer one more time."
"You got it."
SCP-θ'
Enter
Click.

WARNING! Security protocols have automatically disconnected this workstation from all virtual networks. As a necessary component of your viewing of this document, this workstation and all nearby devices and writing media will self-destruct within 2560 seconds.
Item #: SCP-θ'
Object Class: Keter
Special Containment Procedures: All information about Document SCP-i is to be contained in Document SCP-θ'. Document SCP-i is never to be referred to outside of this document. █████ is never to be referred to under any circumstances. Document SCP-i does not officially exist. This document does not officially exist.
Description: SCP-θ' designates Document SCP-i, a nonstandard piece of Foundation documentation which is dedicated to recording the Special Containment Procedures and description of █████. █████ is an informational construct with severe counterconceptual and infohazardous effects. As such, information about █████ and, by extension, Document SCP-i, is highly virulent and becomes more hazardous with increased volumes.
When left in a stable state, information about █████ and SCP-i have a tendency to auto-replicate, increasing its hazardous traits and the possibility of mnesticized individuals coming into contact with that information. Because of this, all information about █████ and SCP-i has been stored in this document due to its naturally self-containing nature.
Following initial identification of an early iteration of █████, Document SCP-i was filed under the number ███. After an indeterminate amount of time, █████ was able to fully infect Document SCP-i through the information stored there.█████ was able to inflict a currently unknown number of casualties on Counterconceptual Division personnel1 before the current containment procedures were implemented. Please see Incident Report: NIGHT MIRROR for more information.

"Hmm. Interesting."
"Interesting, yes. But I can't say that there's much usable information in there," Liz replied.
"Sure there is."
"What?"
"There's plenty of information, you just have to find it. See, now we know that there is something that we're not supposed to be able to know about. We know that information about it has some kind of bleed effect. And we know that there's another big question we should be asking about this."
"And what's that?"
"What is the Counterconceptual Division, and why don't we know about it?"
"Maybe it's defunct. Or maybe it's disinformation, and we don't have one."
"Most people would say that we don't have an Antimemetics Division either."
Liz stops and ponders this for a moment.
"I need to go tell Wheeler, don't I?"
"Yes, and I'm coming too. This whole experiment was my idea, after all."
"Alright. Just one more thing before we go."
"What's that?"
"What is today's date?"
"Oh, that's easy. Today is…" Elise hesitates. "Sorry, what was the question again?"
"What is today's date?"
"Oh, it's… When is it? When?, who?, what?, how?, why?, where?…"
Liz watches as the wrinkles smooth out and color returns to the hair of the disoriented woman in front of her. Turning back the clock does wonders for someone's looks.
"Sorry love, can't have you interfering just yet. Too dangerous for you."
Elise begins to spasm and groan in the chair.
"I wish that I didn't have to age you so far back. With a normal researcher, I could just send you back a few hours. But you've been on mnestics for, what, almost two decades now? And I have to get all of them out of your system to make sure that you can't remember."
Elise's muscles relax as the changes begin to slow.
"Now come on, let's get you to Wheeler. You have quite a bit of catching up to do. On the bright side, you were almost ready when you joined, so it shouldn't take too much for them to get you trained back up." As she half-supports, half-lifts the newly young woman out the door and down the hall, a small frown forms on the lips of Elizabeth Day.

Footnotes
1. The 25 countable casualties were caused by targeted temporal regression of memories.