...
Two time travellers sat across the table from one another in matching lab-coats, hands folded, eyeing each other suspiciously. Dr. Thaddeus Xyank pulled his glasses from his face, rubbed the bridge of his nose, and set them back in place.
He had seen it himself. They cordoned off the hallway during school hours on February 2nd, 1954 under the guise of electrical maintenance. In a weathered pair of overalls he stood with arms crossed and watched as two lizards materialized out of thin air and dropped to the ground. He ordered the wing left closed for another three hours, had some panelling replaced, and thanked the principal for his patience before departing for home through the men's room door. That brought the number of organisms recovered up to 84%, and the old story of ‘I don't know what happened' stopped making any kind of sense.
That was 25 minutes and 16, 17, 18 seconds ago.
“Alright,” Thad said, picking up the remote next to him and mashing a button. On the wall, a recording played of D-48120 walking down a dilapidated hallway before suddenly disappearing at the end. It ran on a loop as he spoke. “Here's my problem with your story.”
Researcher Daniel Ambridge, also known as D-48120, let his head hit the desk, and a soft exasperated chuckle escaped his lips.
“One,” Xyank continued. “You're the only sapient being known to have passed through SCP-664 and come back prior to your disappearance.”
“Yes, but you can't very well check on those squirrels, lab rats, and pheasants, can you?” Ambridge said with a smirk.
“Don't interrupt me,” Thad ordered. “Two: yes we can and have checked on all of those squirrels and lab rats and pheasants and terriers and even that pair of anoles you sent out at the same time, and even when they have come back 50 years prior, they all come back to the same geo-relative location. You did not.”
“Well I guess I'm just lucky,” Ambridge replied, head still resting on the table.
“Three,” Thad continued, losing a bit of patience. “Your time at the Foundation, and specifically working on SCP-664, predates all human testing.”
Ambridge stayed silent, but his head came off the table.
“By itself that's not much, but I've checked your logs as well. You briefed every human test subject prior to their exposure, and performed the debriefing of all but…” Thad rolled his eyes up to check his notes briefly. “D-78221, who arrived at 0952 this morning. Now, pardon my saying so, but this confluence of events doesn't look particularly good for you.”
“What are you, a cop?” Ambridge sneered.
“No, I'm a theoretician,” Thaddeus offered. “We're much more precise.”
Mr. Ambridge leaned back in his chair, crossing his arms. Whether it was a personal grudge about his story not being believed, or frustration at two weeks of incessant questioning, scanning, and probing, Thad couldn't tell. “Why would I lie, hm?” Ambridge gestured broadly to the room around him. “You've got me! It doesn't matter what I say, you're not going to let me go. I know the drill. We received the same training, answer to the same people, swore to uphold the interests of the Foundation and its objectives. So what do I have to gain?”
“A method of nearly untraceable escape the moment someone turns a blind eye,” Thad said, very matter-of-factly. He pulled D-78221's deposition from his briefcase and laid it on the table, turning it and sliding it so Ambridge could see. “I have a sworn affidavit saying that our recent arrival was coached by you regarding how to control his temporal displacement prior to his departure.”
“Oh, so he just came back on his own?” Ambridge asked with his eyebrows raised.
“After a week in Atlantic City in 1989, yes.” Dr. Xyank slid the photographs across the table. “Apparently at his debriefing you were supposed to give him the rest of the puzzle?”
Ambridge looked at the photos and said nothing.
“He said something about a ‘white plain'. Said you were going to teach him how to get there from anywhere, but didn't say how. Is that what the debriefing was going to be about?”
Ambridge swallowed and continued to say nothing.
“… Instead, you were actually going to drop a meme in his head and make him forget the whole thing, weren't you? Had to keep yourself unique or the chances of a successful escape later drop close to nil. Please, stop me when I start to go astray; I'm very interested in how this was supposed to work.”
Ambridge looked up at Thad from under a furrowed brow, lips drawn tightly. At this point, he didn't have to say anything. He knew he was fucked.
“Confidentially? I don't even care if you use it, we'll get around to finding you eventually. I just want to know how you plan to do it.”
“Why?” Ambridge spat, crossing his arms. “There's no way I'll get the chance now anyway. What good would it do?”
Dr. Xyank smiled, and pushed his glasses up his nose. “Because I want to know. I'm a theoretician. This is what I do.”
There were two hard knocks on the interrogation room glass, and Thad took to his feet, smoothing out his tie and straightening his coat. “You think about it for a while. If I like your answer we might have a place for you.” Without delay, he walked to the door and was buzzed out. In the dark room on the other side of the mirror, Marcus Kitterman had the phone pressed into his shoulder.
“There's a call from a Dr. Charles Anborough, L4. Said he has something you might want to look at.” Marcus held out the phone. “Line's secure.”
Thad took the receiver and pressed it to his ear. “Hello Dr. Anborough, this is Thad Xyank. What can I do for you?”
“Yes, Dr. Xyank, hello,” came a surprisingly deep voice through the receiver. “I called because… well I may have something relevant to your field of study here, and was looking for your input.”
“What's the initial appraisal?”
The man on the other end of the phone sighed. “Well, there's definitely a temporal element. Looks like a Safe-class SSUIS2 with a fixed temporal dilation pattern. Normally I'd just bag it up but—”
“Then do what you would do normally, Dr. Anborough,” Thad interrupted. “If you absolutely need someone from Temporal Anomalies, I'll be happy to send one of my JR's down there to run the watch test with you. Just now I'm in the middle of an interrogation regarding an anomaly which is much more subtle and difficult to define.”
“SCP-664; I've read. That's why I'm calling. The brief you logged this morning about D-78221? Particularly the excerpt about the ‘infinite white plain'.”
Thad's eyebrows took the liberty of a brief visit to his hairline. “What about it?”
“…I think we've just discovered it.”

“I just don't know…” Charles said, looking solemnly at the fragment of wall in front of them. “I mean… I've seen portals before, of course, but normally there's some kind of method to them.”
“If there was a method, Dr. Anborough, there would be no anomaly,” Thad said, scratching below his nose. The door was not much to look at. Just a little trap door inset in what was left of a wall. Might have been a meat-locker once, or a dumb waiter, but none of that was left now. On the other side, the wall was flat and impenetrable; the repeated grinding of a diamond carbide drill bit had proven it.
“I thought you didn't believe in anomalies,” Charles chuckled.
“I don't, but I'm open to new evidence.” Thad walked up to the door and rapped upon it with his knuckles. It sounded hollow, almost flimsy. “How much analysis have you done on this? Any kind of radiation leakage? Interesting x-ray patterns in the wall? Thaumaturgic signatures?”
Charles shook his head and walked over. “Not a thing. It's clean, it's been stable since we brought it into custody last month, and no anomalies present in the rats we've sent through and back.”
“What about your time signature?” Thad asked. “You said there was some temporal dilation.”
“Stopwatch and camera test says 1 to 140, but only when the door is closed.”
Thad whistled softly. “Quite a ratio. Do we know if it's causally isolated?”
Charles blinked twice. “…I'm sorry, what?”
Thad sighed, and looked around at the debris by his feet. he picked up a piece of charcoal that seemed sufficiently soft and found a blank spot on the wall. “Okay… when the door is closed, we've got a situation that looks kinda like this. One nice straight world-line, the one we're riding…” He quickly marked a long horizontal line. “…And another running in parallel.” With all the art of a 60 year old tenured math professor, Thad drew a tight sinusoid over the first quarter of the horizontal line.

“…You said this thing is safe, right? I'm not going to get some kind of cancer if I put my wrist in there?”
Charles shrugged and shook his head. “A month plus, no incidents. I wouldn't, but—”
Not waiting for him to finish, Thad opened the door and thrust his watch hand inside. The poetic, vast white emptiness on the far side of the door was lost on him. Well, not lost, but surely on hold. He counted seconds and watched the 442i on his wrist keep perfect time with him. “Alright.” The door closed with little ado as he returned to his diagram. “Door opens here, and closes here.” he said, drawing two quick slashes, and then a second straight line above the short stretch of the world line between them. “And apparently, the temporal dilation stops, and the two segments become causally linked.” This, he represented by drawing four dots, evenly spaced, on either side of the two lines. “Then, when the door closes, the dilation resumes as before.”

"With me so far?”
Charles scratched some stubble on his cheek and nodded. “Yeah, I think so.”
“Good. So let's say we… Damn, I need another color.” Thad scanned the ground and found a piece of clay to his liking. He drew a small yellowish stick figure on the line “This person goes through the door, here, and does some thing, I know not what, on the other side.”

“And he doesn't want to stay in there forever, of course.” A brief flash of a memory rocketed across Thad's skull, and he violently shook it away. “So he comes back out.”

“At some point, let's say here on the world line,” and in so saying, Thad flipped the clay and began writing with a much darker red color, “someone with a grudge decides to travel back in time, and kill our man before he ever stepped foot inside the door.”

“We know, of course, that means that our little stick man never lived a life leading up to the door, and never entered it, and the future of the world-line changes instantaneously into a world where the stick man doesn't exist.”

“However, if the dilated region is causally isolated—which it may have to be to preserve a stable dilation ratio—does that erase his presence from the world behind the door? What's more, and perhaps a more important question, does his retrocausal murder prevent his ability to re-emerge later?”

Charles looked at the diagram good and hard for a few minutes, glancing back and forth between it and the expectant eyes of the time traveller standing next to him. It almost made sense. Almost. It seemed like it shouldn't be that way; that if the hypothetical person was wiped from existence on one side of the door, he must be wiped from the other, too. On the other hand, there shouldn't ever be such a door; one which had more time on one side of it than the other. He had read the papers about tachyon field theory, and at the time they seemed to make sense but…
“How would we ever test that?” Charles asked, finally bringing his hand down from his chin. “To us, it just looks like some unidentified anomalous person appeared on the other side and tried to come through. We'd bump the anomaly up to Euclid if it happened once, and probably Keterize it to be certain if it happened more than a dozen times.”
“Well we cou—” Thad started, but did not finish. “Huh… you know you're right. We'd need a third frame of reference to… But we can't do that unless…”
And while the doctors stood in uffish thought, staring at the diagram with their teeth in their mouths, the tiny door inset in the wall shuddered and burst outward. A human arm reached out, flailing for anything it could grab onto. In a snap of adrenaline Thad Xyank and Chuck Anborough jumped backward, drew their sidearms and stepped back double quick, ordering the anomaly to stay right the fuck where it is as bigger men with bigger guns burst into action behind them and moved up. There was a lot of yelling and confusion from the construction crew as another arm came into view, raised in defensive surrender. The docs dropped their muzzles to low ready like clockwork as two guards moved around them and set a bead on whatever hellish thing was daring to feign surrender and draw them closer to its enormous hidden gaping death maw of razor-sharp doom. Still retreating, steady, smooth. Slow is smooth. Smooth is fast. Blood coming out of the door, and a scared, squirrelly voice they could still hear from 10m away as they holstered the weapons and turned to book it. Any minute now there'd be a vortex or a death howl or a hail of gunfire, and by god they wouldn't be alive to care for long if they stayed this close. They didn't stop until they were 100m away behind a quarter inch steel plate, shepherded around the bend by a hard case in tactical black shouting ‘Go-Go-Move it!-Go!' The whole ordeal was over in less than 20 seconds.
“FUCK!” Charles screamed as he folded at the waist, propped up on his knees eyes plastered shut. A decade working with Keters puts the fear in you. After handling the unhandleable, training that can get you over the wall to safety is all you can really ask for. “Fucking safe class! This was my vacation project!” The pinky-side of his fist struck the plate of steel as he slid down to the ground.
Thad raked a hand down his face and took a deep breath. Stupid. Fucking stupid. Fucking academic stupidity of the highest order and thank god he had gotten re-certified this month. He had put his hand in that thing! And then just stood around next to an active anomaly drawing curly-q's and stick figures. If he had wanted to discuss a subtle variant of the grandfather paradox he— … Wait a minute.
“…You know, it is rather convenient, isn't it? Us standing there, talking about how if it worked, we'd never know the difference, and not a minute later an unidentified humanoid busts through the door?” Thad said, the smallest hint of a smile tugging at the corners of his mouth.
“This is Captain Crawford, come back Rally 2?” the radio on the nearest guard squawked.
“Rally 2 here,” the guard answered.
“Situation under control. Unidentified humanoid in custody. We're uh… We'll be maintaining a 10m radius around the object.”
“Understood,” the guard replied and raised his voice to address all the other poor schmucks at Rally 2 that everything was fine, and just to be safe, don't cross the tape unless you have someone to hold your hand for you.
“Hey stop me if you've heard this one before,” another voice came over a nearby radio. “The Skip says he knows who we are, and wants to talk to someone from ‘Delta-Tee'.”
“…What are you saying?” Charles asked as the sanity crept back into his stare.
“I'm saying… I'd like permission to interview your detainee,” Dr. Xyank replied. “You know. Just in case.”

Agent Burt Tomlin's head was in his hands as he heaved a heavy sigh. From the corner of his eye he spied the interrogation room mirror, and silently asked his reflection why he had agreed to come in so damn early this morning. “So, let me get this straight…” Burt continued, turning his attention back to the unkempt, red-haired, befreckled HCP-1 across the table. “Your name is Kevin McDougal, and you're some kind of time-travelling Foundation Agent, sent from the future to test…what did you say again?”
“Yeah. Well… I mean, no. I'm a Junior Researcher under Dr. Thaddeus Xyank of Research and Containment Team Δ-t. I was working with him trying to link two known anomalies, SCP-664 and SCP-2400.”
“Uh huh…” Tomlin said, rolling his eyes. “Even though we haven't got a 2400?”
“Yes, but you will! For Christ's sake, it's where I was picked up!” McDougal exclaimed, shaking his hands in the air. “We were interrogating a Daniel Ambridge about 664 when Dr. Xyank got a call from… someone, I don't know who, about 2400. Based on the information we had, we decided to test if they were connected by sending me through. That was April 10, 1998.”
“Right, right,” Tomlin said, taking a sip of coffee. “Except… I gotta tell you, this sounds like a pretty gross breach of protocol. If what you're saying is true this… What was that name?”
“Thaddeus. Xyank.”
“That's it. This ‘Xyank' character…he'd have to be a pretty big wheel. If you were a JR, you'd know cross-tests are almost never approved. And sending someone with a clearance through it? I mean, why wouldn't he just use a D to do it?” Tomlin said, feigning disinterest.
McDougal rubbed his eyebrows and shook his head. “He said he needed someone he could trust.”
“Of course he did,” Tomlin said into his mug, hoping after the fact that it was too soft for the mark to hear. Another slip-up like that and he might give something away. “And why did he trust you?”
“He hired me and my buddy Marcus right out of grad school! I've worked with him for over three years on all kinds of temporal anomalies.”
“Oh yeah, where was that?”
“Ithaca State,” McDougal replied. “…You know, the one in New York?” He was clearly losing his patience.
“Easy there, wise-ass,” Tomlin said with a sneer. “No one likes this process, but mouthing off to me isn't bound to win you any favors.”
Two knocks on the interrogation room glass and Tomlin perked his head up. “…Alright Mr. McDougal, you just sit tight a minute.”
Outside the room Marcus Kitterman was a wet dog, soaked to the skin in sweat. Thad Xyank had his arms crossed, brow furrowed, and lips pasted together in a thin black line. “Chuck Anborough just called,” Thad said, eyes not leaving the kid in the hot-seat. “O5-8 just designated SCP-2400.”
“Jesus,” Tomlin said, head hanging loose on his neck. “What about this shit with 664?”
“It's legit,” Thad said, still stolid. “I had that conversation three days ago. He said he went through on the 10th?”
“Yeah.”
“Good,” Thad said, nodding. “I mean, it sounds like me. It seems like something I'd want to test, but I never expected to have an actual paradox on my hands. We still have a week to track him down. We can still send the original through if we need to.”
Kitterman shook his head violently. “Noooo you can't.”
“Oh? Pray tell why not?” Thad asked impatiently.
“…What he says is right. We knew each other in grad-school. And high school. And kindergarten. Kevin and I are like best friends. They used to call us ‘cookies and cream',” he said chuckling. “…He's about the only one I kept in touch with after I was hired. I figured it was alright, since he got all the way to the live interview, like I had, but… You remember that week I took off last March?”
“Spit it out, Marcus,” Tomlin demanded.
“He's dead, okay? I went to the funeral, I saw his body. He was on his way to work one morning and a car cut him off, broke his neck.” Kitterman was very nearly in tears, and Tomlin very nearly felt like a heel.
The color drained from Thad's face as it came to him. This was a situation he could not win. The child on the other side of the one-way glass, if genuine, was the end of history as mankind knew it. Dr. Xyank was in a position now that required history to change in order for history to be preserved. How does one maintain the status quo when the status quo is in indeterminate flux? Which status quo do you preserve? Without thinking, he turned to a nearby computer console, pulling up his notes on Kitterman's hiring process and who was brought on at the same time and wouldn't you know it? There was Kevin McDougal. His application had a note written in red pen in the upper right hand corner.

Possible connection to undiscovered anomalies. Do Not Hire
-Tx

Thad knew that name sounded familiar somehow.
“It looks legitimate,” he said softly, turning back to the window and resting his forehead against it as Kitterman and Tomlin looked at the screen and shared nervous laughter.
Kevin McDougal, Age 32. A young man whose life, as he knew it, never happened. And never could happen.

From: thaddeus.xyank@foundation.net
To: o5-12@foundation.net
CC: athena.anastasakos@foundation.net; marcus.kitterman@foundation.net; bertrand.tomlin@foundation.net
Subject: Re:Frame of Reference Proposal
You are correct, continuing experimentation along these lines will necessarily alter the course of history, and perhaps in unpredictable ways. However, as demonstrated in previous attachments, there is sufficient reason to believe that the interactions between SCP-664 and SCP-2400 have already caused such an alteration. Whether this was done intentionally by an alternate iteration of myself or occurred naturally is irrelevant.
The purpose of this proposal is not to give myself or the Temporal Anomalies Department carte blanche to run amok about time flipping switches and pulling levers. The mission of RCT Δ-t will remain unaltered from that put forth in our previous discussion, until such time as sufficient evidence is collected to warrant a re-visiting of those goals.
All I'm requesting is that you allow me to create a stable, static causality, immune from the effects of causal tampering. From this external time-line we will be able to meaningfully measure the rate or frequency of historic shifts, as well as allowing agents on temporal retrieval or research missions to have a stable home base to which they may return. The genie is already out of the bottle, so to speak. If we ever mean to put it back in, we have to be able to track its movements first.
Thank you for this consideration.
Thaddeus Xyank, PhD.
Temporal Anomalies Department Chairperson
thaddeus.xyank@foundation.net | Ext. 1780

From: o5-12@foundation.net
To: thaddeus.xyank@foundation.net
CC: athena.anastasakos@foundation.net; marcus.kitterman@foundation.net; bertrand.tomlin@foundation.net
Subject: Re:Frame of Reference Proposal
This request has been approved by a 7-5 decision.
Do not make me regret my vote, Thaddeus.
O5-12

…

Part Three: Erstwhile and Again | Hub | Part Five: Document 1780-WL