"So then, I'd say it's definitely not all in your head," Evelyn offered by way of confirmation after listening to Samantha's explanation. "There should at least be something tangible for me to find."

"I guess?" Samantha shrugged. "David's been watching me for the past couple of hours, and he said that there's something noticeable going on."

"Sure, but your own perspective counts for something, too, right? You don't need someone else to tell you that you're not okay."

"Honestly? I'm not the best judge right now," Samantha replied with an expression of defeat. "Like, on our way back to the house, we got lost in an endless tunnel of some sort of sticky darkness, and then this swarm of giant bees started attacking my head from the inside. It hurt so bad I actually bit off my own tongue. But now, it turns out that the whole thing apparently never even happened. So, like, what the hell do I know?"

"That sounds pretty vivid for something that didn't happen."

"I can still taste it."

"Damn."

"I know, right?"

"Well, maybe that's a clue. It's something for me to look for, at least."

She took Samantha's hand and tried injecting mana to restart her visualization. It didn't work.

"You mean look for the bees?" asked Samantha.

"Bees?" Evelyn blinked and shook her head, "No. The bees weren't real. No, I mean I need to look for more subtle clues. I can't just rely on prior assumptions about what's possible."

She tried the visualization again and failed again. "Why isn't this working?" she muttered to herself.

"You should probably try turning it off and on again," Samantha offered, uselessly. "Oh, take it out and blow on it. I've heard that helps."

"You're not even old enough to get that reference."

"Two years older than you. Anyway, I was trained on the classics."

"Ah, this must be it," said Evelyn, looking at her hand, "I'm probably just out of mana."

"I'll go get you some gems," David offered and started to get up. Evelyn noticed how Samantha suddenly tensed and gripped his arm as he started to move.

"Don't bother," Evelyn waved dismissively. "I'll just use my white mana instead."

Blue mana was the most reasonable type to use for forming this kind of link. Of the four fundamental mana types that they had cataloged, Blue was the least substantial and most energetic. Unlike the others, Blue directly affected pure energy rather than any form of physical matter. This made it perfect for moving around energy and information rather than objects, and ideal for things like this type of external visualization. However, her pool of blue mana was small in comparison to her natural stores of Red and Yellow. And while she didn't go through it very fast, she could feel that she had exhausted her entire pool by repeatedly stopping and restarting her visualization process.

Fortunately, she also had a respectable supply of white mana that she normally tried to avoid relying upon. White was a fifth, "wildcard" form, composed of a sort of superposition of all types of mana at the same time. It could be converted effortlessly into any other kind, including complex combinations, right when you needed it. There were drawbacks: it would be consumed far more rapidly than one of the basic forms and it recharged more slowly, but the flexibility wasn't to be underestimated.

Evelyn pushed a bit of her white mana through her hand where it instantly transformed into the appropriate collection of mana patterns for linking her mind to Samantha's body. Since she was using White this time, she got an unexpected bonus of improved clarity. Instead of needing to manually figure out what patterns would work best and consciously shift her mana as close as possible to the right fit, the white mana responded directly to the context and "just worked." This accuracy provided her a much clearer picture for her visualization than she normally worked with. The clarity provided not only improved detail, but also better temporal resolution, allowing her to follow the neural connections and actually see the signals move through Samantha's brain as if in slow motion.

She wasn't quite sure what to look for. Originally she'd just been looking for anything obvious, like a foreign object or a lump that behaved abnormally. Nothing like that had shown up. She realized now that it wouldn't be that simple. She was going to have to actually be patient this time, and sit and observe for a while before drawing any conclusions. This wasn't Evelyn's strong point, but she'd do it for a friend.

She watched the patterns of neurons firing, of signals forking and recombining. She sped up her own perception of the visualization to make the real world look like slow motion. At normal speed it was all a buzz of activity, but slowed down she could see the individual pulses of signals move like waves across Samantha's mental pathways, forking and branching like lightning. She sat and observed until it felt familiar and she could reliably predict what she saw. She even found a certain beauty in how the patterns would often send out distant--

"Wait, no," she thought, "that's not how brains are supposed to work."

The branching signals didn't always quite match up; they weren't always connected. Often a signal would stop at some point and restart somewhere entirely different. Not a new signal, it was a continuation of the same one, but with no connection in between.

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"That shouldn't physically be possible."

Brains were complex and confusing things, for sure. But each individual cell, at least, was simple and predictable. Some things just didn't happen. If you were to watch an individual neuron on its own, you would always see--

"Except, no. There's something else there, something just beyond view..."

It was like watching a piano play itself. Evelyn knew there was a part of the picture that she couldn't see, but she could tell it was there by watching what it did. Biology couldn't do this on its own; this had to be mana.

Evelyn hadn't ever seen mana, itself, in her visualizations. After all, mana was usually only visible in extremely condensed form, like the red barriers or glowing vapor from yesterday. On the other hand, internal visualization had nothing to do with eyesight, which meant that the only logical reason why Evelyn couldn't visualize mana was because she didn't know what it looked like and wouldn't recognize it.

She'd never known what to look for. Until now, at least.

There must be some invisible link between the disconnected signals; the piano doesn't play itself. As she closely examined the spaces between, she began to see subtle variations in the density of... something. It seemed like space itself, or just reality. It was the background; the background... had a shape.

"Huh," she said out loud when she finally understood what she was looking at, her brows knitted in confused concentration.

The answer raised far more questions than it resolved, but at least she understood why it was so hard to see the mana inside the body. That'd be like trying to see the water inside the ocean. If you had to ask, then it was the wrong question. It took her a few minutes to rearrange her thoughts enough that what she saw would start to make sense.

Mana was more than just an invasive force that changed how bodies worked. Instead, it integrated into everything as though it had always belonged. It was a puzzle piece that fit right in the middle, not something tacked onto the outside like a barnacle. Nowhere was this more apparent than here in the brain.

Gary had been right that mana was changing the way neurons worked, but it went so much deeper than that. Neurons seemed almost purpose-made to push and pull mana, with all the tiny intracellular structures working together to handle the complexity of that task. Neurons were designed to be mana channels. Biology made a ton more sense once she saw how mana interacted with it all.

These facts all felt familiar as well. Evelyn had known this, all of this, yesterday when she stood in the jewelry shop swimming in a vortex of glowing mana vapor. The vague sense of familiarity helped guide her discoveries now and let her confirm when she was on the right track. But it also left her feeling uneasy: she had perfectly understood everything she was discovering now, and had decided to alter her own body for some reason as a result. She had fixed something that would otherwise prove disastrous, and had expended a truly staggering amount of power to do so. But why? What was it?

She had known at the time that something was dangerously, fundamentally wrong. Although she had fixed it, she had only fixed herself. And now, Evelyn had no idea what dark truth her past self had seen. A truth that, in order to address it in a single person, she had blown enough mana to vaporize a small town.

Perhaps Samantha's troubles were somehow related. And if so, maybe this could be the key to uncovering at least part of that mystery.

Applying what she had learned, Evelyn tried to map out how the invisible connections worked. Just trying to see them at all gave her a headache, like trying to read transparent lettering on clear glass. She could only really see the effect, and only when the connection was actively sending information. It was slow-going and confusing, but she stayed focused and persisted: minutes, perhaps hours. It felt like days given how the visualization stretched her perception of time. She would never have had the patience for this under any other circumstances, but she refused to give up on Samantha.

A pattern became clear over time, an entire layer of intangible connections spanned between the neurons, maybe even more layers than one. It was an emergent property rather than anything physical, which relied entirely on mana to operate. Since the function of neurons was mostly about their connections, this was like having even more brain capacity packed into the existing cells. She effectively had an additional "magic brain" woven throughout the structure of her normal one. The magic counterpart of Samantha's mind was mostly independent, but it was connected in a way that would still affect many of her normal brain functions, especially her emotions, instincts, and memories.

This discovery on its own was huge. It explained so much. Evelyn was about to take a break and share what she had learned, but then she noticed something disturbing.

While the "magic brain" was, for the most part, stable and tightly integrated, still many parts appeared to be chaotic and disconnected as though they didn't fit right. Some connections were broken and just leaked stray mana into the space between, while others seemed to be cross-connected and sent working signals to the wrong places. If these stray signals got too strong, they would sometimes impact the working ones and knock whole pathways off-balance.

Even more intriguing: the more primitive, animalistic brain regions all had perfectly working mana connections that seemed stable and orderly; they worked just fine. The chaotic connections only showed up in the complex, higher-order brain regions -- the regions that we would say "make us human" -- the magic in those areas was a mess.

"What the hell is going on?" she muttered under her breath.

"Is my head hopelessly broken?" Samantha asked with a grimace.

"It's not that," Evelyn responded, not wanting to get into the details just yet. "I've noticed something that I don't understand. Just... give me a moment."

While her initial impression made her think that she'd found the culprit, something didn't feel right.

Thinking on her discovery a little more closely, one point stood out: it was odd that the more primitive parts of the brain integrated better with magic, while the more recently evolved regions seemed like they didn't have a place to fit in. There shouldn't have been such an obvious distinction. Even though the different brain regions served different purposes, they were generally made of the same stuff and occupied a lot of the same spaces. There wasn't anything physically different that would explain the different behavior. And yet, the distinction was suspiciously consistent everywhere she examined.

She didn't want to jump to any conclusions, but this didn't feel like merely a "Samantha problem." Mana was everywhere now, affecting humans and animals alike, overturning the balance and changing the rules. And if the determining factor in how it all fit together was based on evolutionary features, then all the members of the same species would be affected by mana in similar ways. Right?

It was far too early to draw any conclusions, but rather than this being a "Samantha problem," this very well might turn out to be a "human problem." Or perhaps a "mammal problem" or even an "intelligent animal problem." She didn't know yet.

Regardless of how it panned out, she wasn't thrilled about the implications.