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Published:
2026-05-17
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2026-06-04
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74,336
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19/19
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Fragile Balance

Summary:

Following a lead on a case they just can’t seem to solve, an accident leaves Mulder with supernatural powers. The same powers their main suspect seems to posses. In a race against time to stop a series of murders, what could be a key to the case instead puts new obstacles in their way.

Notes:

For @Calimanc, who sent me a prompt exactly two years ago. I can’t *believe* how long this took, but it’s finally done! It grew from a short fic of a few thousand word into a novel-length thing with plot, which was unexpected but fun to write.

A lot of people have helped me along the way through beta-reading and cheerleading: urlovingfriend, @unremarkablehouse, @bakedbakermom, @baroness-blixen, and @bookishscully. Thank you all so much; this fic wouldn’t exist without you! The original prompt came from a list by @cecily_sass, so this is really for you too!

There are some content warnings that contain spoilers, so I will put them here for anyone who wants to check before reading.

Spoilery conent warnings

All of these are mentioned in the investigation of the case and happen off-page, in the past, and *not* to Scully or Mulder.
- Cheating
- Mention of domestic violence
As this is a case file, there will be canon-typical violence. Please feel free to message me on tumblr @thursdayinspace if you have any questions.

Set in late season 5.

This is a finished fic and I will be posting a chapter a day.

Chapter Text

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Not for the first time in his life, Mulder wished that he could see in the dark. He cursed under his breath as he slipped on a loose stone under his feet, his hand flying out to steady himself against the smooth, cold rock of the tunnel wall. The narrow beam of his flashlight could only do so much; this deep underneath the hill, the darkness was complete. At least neither he nor Scully were claustrophobic. Not that it would have stopped him—he knew himself well enough to know that he would have gone either way. He focused his attention ahead where Scully was just dodging a low-hanging stalactite—or stalagmite, he could never remember which was which—before disappearing around a bend. The sound of her footsteps echoed back to him slow but sure across the uneven ground. Taking a deep breath of damp-smelling air, Mulder wiped his hand on his pants leg, and then he followed her.

They had been down here for at least an hour, making their slow way through winding passageways that were connecting a series of small caves and narrow chambers, and there was nothing. Absolutely nothing. He had a strong suspicion that it was only a matter of time before he’d get his well-deserved “I told you so.” At least they’d taken the time to change out of their suits and into something more practical, including proper shoes, for an afternoon of what was turning out to be pretty pointless spelunking.

The space between the walls grew narrow until he had to wiggle his body through a crack in the rock, knees bent, squeezing his way through sideways. He kept his eyes on Scully who’d had far less trouble sliding through this tight passage, and had now stopped a few feet ahead. Her straight posture and the way she was turning her head from side to side made him guess that she had found another chamber.

“Anything there?” he called out to her.

“I’m not sure.” She stepped around a low outcrop, just a little further for a better look. “Looks like all the others.”

He had to duck his head the rest of the way to the small arch where she was standing, stubbornly clinging to the dwindling hope that he hadn’t dragged her all the way down here for nothing.

“Mulder, I really don’t think there’s anything here,” Scully said, shining her flashlight around a spacious cave, the biggest one they’d seen so far.

He stepped out of the low tunnel behind her and straightened his back with a groan. For maybe the first time ever, he envied Scully for being so short. Some passages were big enough for him to stand up in, but he’d been doing a lot of walking hunched over, and it wasn’t his favorite thing in the world. His neck felt cramped and the ache between his shoulder blades was getting harder to ignore.

“It’s just more rock,” Scully said, lifting a hand to rub her own neck. “Don’t you think it’s time to turn back? This is not leading us anywhere.”

He lifted his own flashlight to let the beam wander along the rough gray walls. “I think you’re right.” He didn’t want to admit defeat, but he knew her patience was running thin. And so was his own, if he was being completely honest with himself. He knew that the only reason Scully had followed him down here at all was that she had no better theory either, no other avenues to pursue. This had been their first new lead in almost a week. If it was another dead end, that put them back to square one. And he couldn’t accept that, not yet. “Let’s just have a look around this one last cavern, and if it’s empty like all the others…” He hiked up his shoulders, not wanting to finish the sentence. If it was empty like all the others, they’d be screwed.

“I think this is the end of the line anyway. I see no other way out of here.” Scully walked further in, and he could see the tension in her shoulders. Maybe she wasn’t claustrophobic, but an hour or more in confined spaces with the prospect of having to walk another hour back to get out seemed to be getting to her anyway. It was getting to him too.

“Yeah.” He took a few steps further into the cave. “Looks like this is it.”

“It would help if we had some idea of what we’re even looking for. Something a little more concrete. We don’t have much to go on.”

“Anything unusual,” he said, feeling like a bit like a broken record. “Just anything out of the ordinary.”

“So you keep saying.” Scully let out a long breath and rolled her neck. “Fine. Let’s get this over with.”

At least this last cave wasn’t quite as dark as the others; there was a small opening in the roof high above their heads which let in a ray of sunlight. Well, he thought, ray was generous. There was a hint of overcast sky that offered pretty much no light at all, but after the pitch-black darkness of the past hour, even this barely there reminder of the outside world seemed like a relief. The glimpse of gray twilight at least managed to lift his spirits a little, along with the slightly fresher air, although the latter might be his imagination. He was seriously starting to dread the long way back, crawling and climbing through the same tunnels as before, only knowing this time how long it would be until they’d have grass under their feet and sky above their heads again. If this was a dead end, he’d owe Scully a nice dinner and no late night calls for the next few days at the very least.

Scully walked off to the right, and he started making his own way along the walls in the opposite direction. He knew that she was right. It had been unlikely from the start to discover something in here of which they didn’t even have a clear physical description, other than that it was a substance. “I guess it was a long shot to begin with,” he said apologetically.

“It was,” Scully agreed. “But…” She looked up at the gap in the roof. “We didn’t have anything else. It wasn’t a bad idea, Mulder.”

“Just rushed, as always.”

“Maybe. But we are running out of time.”

If she was starting to reassure him now, he thought she must be feeling as desperate and hopeless as he was. Which was not surprising. It happened when you kept running into walls in an escalating case.

A series of murders, and a suspect who possessed what Mulder was sure were psychic powers. Powers that supposedly came from a substance hidden somewhere in these caves—according to the suspect’s girlfriend, a young woman by the name of Amanda Crane. A young woman who had come forward and finally given them something to go on, after too many days of having no more than a whole lot of nothing. Finally a solid lead, a name. Derek Thompson. A man who was not only Amanda Crane’s boyfriend, but also her history professor. A man who, according to her, could read minds, thanks to something that he got out of this cave.

It had been a solid lead. It had seemed like a step forward after poking around in the dark for so long, but it wasn’t enough. And it certainly didn’t help that their precious informant had disappeared from protective custody just a few hours after giving her statement. Disappeared from right under their noses, with absolutely no explanation.

“I still think it’s possible that Amanda Crane was in on it,” Scully said, not for the first time.

“No. I don’t believe that,” Mulder argued, also not for the first time. He switched his flashlight from his right hand to his left to run his fingers over a rough patch of stone. “Derek Thompson didn’t have an accomplice. He was working alone. I’m not sure about many things in this case, but I am absolutely sure of that.”

“I don’t necessarily mean that she was actively helping him,” Scully pointed out. “But she may still have known all along what he was doing. It’s not impossible.”

“You think she knew for weeks that he was going around killing innocent people, and only decided to rat him out yesterday?” he continued the familiar debate. “She didn’t even tell us about the caves until this morning because she was afraid we wouldn’t believe her.” Of course he had believed her. He had believed her instantly.

“Don’t just dismiss the possibility.” Scully turned and shone her flashlight directly at him. “Think about it. She may have known about the killings, but she didn’t know about his other four girlfriends. She snapped. Everybody has a breaking point, even accomplices to murder.”

“So, you’re saying she turned a blind eye until she discovered that he was cheating on her? And then wanted, what, revenge?”

“It is possible. Maybe it was the last straw. Wouldn’t you be angry if you found out your partner was dating at least four other people on the side?”

He shrugged. “Of course I would be. Who wouldn’t be?”

“So she found out, and that’s what pushed her over the edge.”

“I’m not ruling it out, but I also don’t believe it.” He paused, biting his bottom lip. Often enough, arguing the same point back and forth in different variations led them down new paths that ultimately led to the truth. But, he had to admit, this time, they seemed stuck. “I don’t think she had anything to do with it. Besides, even if she was angry at him, contacting us was still a big risk to take, for herself and her own safety. It meant implicating that she might have been aware of his actions all this time, in which case she knew she wouldn’t get away unpunished. And she seemed way too smart for that to me. Didn’t you think so?”

“Okay, yes,” Scully agreed. “But the other girlfriends are not the only factor we have to consider here.” She sighed heavily. Fatigue sat in the slump of her shoulders. And he knew she was about to whip out the closest thing she had to a knockout argument. “The last victim was her friend, Mulder. She had known Lydia Abbott for three years. If Thompson had killed her friend… wouldn’t that at least be enough to push anyone over the edge?”

“Yes.” He nodded at her across the wide space, then trailed his hand over a small outcrop in the wall. He was still touching nothing but cold, solid rock. “I agree that Lydia Abbott is an important part in all this. Just not in the way you think. After all, Lydia was the one who warned Amanda Crane about Thompson in the first place.”

Scully shook her head. “We’ve been over this, Mulder. It doesn’t look like Thompson murdered Lydia Abbott simply to silence her,” she argued. “She was stabbed through the heart, in exactly the same way as all the other victims. Her body was arranged just like all the others as well. On her back, her eyelids taped open, and the cross drawn on her forehead in her own blood.”

“That’s my point,” Mulder said. “She was a part in the series of murders, not a random, isolated killing. I think he would have killed her one way or another. But I think that Lydia was onto him, and that’s why she contacted Amanda. I think that Thompson had already chosen her, and that Lydia knew it. She was afraid, or she wanted to protect her friend, or possibly both.”

“And it’s also still possible,” Scully pointed out, “that Amanda already knew about it all, even before Lydia contacted her. It is entirely possible that she knew, and simply disagreed with Thompson on this one particular murder. And the fact that Lydia told her and warned her is simply a convenient coincidence that lets her pretend she wasn’t in on Thompson’s plans prior to that.”

“I don’t believe that.” Mulder took a breath before continuing, before bringing out his own closest thing he had to a killer argument. “Amanda Crane knew about the cheating for a week or so. But she didn’t get Lydia Abbott’s messages about Thompson stalking her until after Lydia had already been killed.”

“Allegedly.” Scully crossed her arms over her chest. “All we have is Amanda’s word for that.”

“No.” Mulder let out a long breath. “There must be something about Lydia that fits the other victims. Something that Thompson read in her mind. Derek Thompson has psychic powers. I’m certain of it, Scully. He got into Lydia Abbott’s mind the same way he got into the other victims’ minds. He knew them inside out. He played on their wishes and their fears to lure them into his traps and—”

“He must have stalked them,” Scully interrupted. “It’s as simple and easy as that. You don’t have to read someone’s thoughts to gather information about them.”

Mulder shook his head. “Three of them didn’t even live in D.C., Scully, you know that. He didn’t have the time to get to know their habits and routines. How did he get to know them so well in days, or hours in one case? The third victim arrived the evening before he was killed on his morning run. All he did in between getting into the city and being murdered was dinner and having a good night’s sleep.”

Scully lifted a hand to her forehead and let out a small, impatient sound. “Nobody can read minds, Mulder. And what about his alibi? The only murder beside Lydia’s that we could even link him to based on evidence is one where he cannot have been at the scene when it happened.”

“What, because one of his girlfriends swears that he was with her at the time? Didn’t you get the sense that she was lying to protect him?”

“You know I did,” Scully said. “But it doesn’t matter what either of us believe, because we still can’t prove it.” She raised her flashlight and squared her shoulders. “Look, be that as it may, let’s look at the matter in hand. We don’t even know what we’re looking for in this cave. Or how it might work. Or what it even looks like. It could be literally anything. We could have walked past it five times already without ever knowing it was there.”

“So what do you suggest we do, then?” Mulder asked.

“Well, as we said, have one last look around and then get out of here, first of all. And then focus our energy on finding Amanda Crane and question her again. You have to find it at least a little bit suspicious that she just bailed after giving us some incredibly vague information. Information about something that nobody could substantiate, but that was just enough to make us curious. If you’re right and Thompson can read minds—which is still a big if, by the way—who says that Amanda doesn’t have the same ability? And if she does—still a big if—she knew what you wanted to hear. So she used that against you, and then she disappeared from protective custody and went into hiding God only knows where. Why would she do that, Mulder? If she were completely innocent? Wouldn’t she be afraid that Thompson might find her and take revenge?”

Mulder bit his lip and took a moment before he responded. Because yes, he did find it suspicious. “The fact that she disappeared doesn’t automatically mean that she ran. People have been abducted even from protective custody.”

Scully nodded, and he knew she was as reluctant as he was to consider this alternative: that Thompson had somehow gotten to Amanda and killed her too, after finding out that she had talked. They had found no body as of yet, but that didn’t mean that they could rule out the possibility.

“Okay, look.” He didn’t want to fight with Scully. It wouldn’t lead them anywhere, but he was equally unwilling to let this go. However, they were slowly diverting from their usual back and forth of challenging each other to having an outright argument, and he hated that. “Time is running out. Thompson isn’t done, I guarantee it, and if we can’t find anything concrete—”

“I know,” Scully said. “I know, you’re right. But this is still almost certainly a dead end, Mulder. I’m telling you, there’s nothing here. These caves are empty.”

“As far as we can tell.” It was disappointing, not just because of the case, but also because finding a source of psychic abilities would have been an amazing discovery. And he felt like he could have used a win for once, even one that had nothing to do with their investigation.

Scully started searching the ground from the middle of the cave outwards in steadily widening circles, while he continued to make his way along the walls. At least this was something he could always count on: their ability to work in perfect tandem even if they disagreed.

He’d made his way almost all the way around the chamber when he saw it. It was right back by the entrance. He almost passed it by, almost wrote it off as nothing. His eyes slid past it, then darted back, and snagged on something… weird. He stopped, then carefully stepped closer, eyebrows drawn together as he leaned towards it. It was something in the rock, something on the surface. He’d noticed it along the way a number of times and thought nothing of it, filed it away in his brain as damp stone, but now he shone his flashlight straight at it. Something twisted in his gut as he examined it. It was an area about twice as big as a dinner plate. And it seemed… wrong. Off. The color didn’t match the rock around it, looking more like a dull silver than gray, and it was shiny and completely smooth. A little like glass, but not translucent. Glossy, almost. Not a single irregularity in the surface. It was so perfect that it was uncomfortable to look at, as if he wasn’t supposed to.

“Scully?” he called. “Come and take a look at this.”

“Take a look at what? What did you find?” The beam from Scully’s flashlight hit the wall next to him, and he could hear her footsteps approaching as quickly as she could walk on the cave ground.

“I don’t know,” he said. “Probably nothing. It’s just—” He reached out, carefully brushing his fingers against it. It was slightly warm to the touch, not cool like the cave wall, and instead of a hard surface it felt spongy, almost liquid, as if it should ripple under his touch like the disturbed surface of a still lake. “I think I’ve got something here,” he called out excitedly, his heart beating faster in his chest. Unable to resist, he pressed in harder, his fingers breaking the surface and slipping into something soft. Something soft that made a tingling sensation spread from the tips of his fingers over his hand to his wrist…

A bright light flashed before his eyes and he felt himself propelled backwards, heard Scully shouting, her voice weirdly distorted. The last thing he felt was the hard impact of his body hitting the floor, knocking the breath from his lungs, and then the world went dark.