Sunset groaned and let her head thud against the desk. She and Pia had finally managed to get almost all of the loose magic in Rivet City corralled, contained and controlled. Even the spontaneous lightning generated by the trees had been stopped thanks to Applejack's idea of sticking taps in the trees and literally siphoning off the excess magic into jars.

Naturally, a lot of magic was being extracted that way, but the science team had put together an efficient system of cataloguing the magic as it was extracted; setting the varieties they recognized aside in vats and selling off the excess to the Brotherhood of Steel at a heavily discounted price. It helped that the city's reopening, and the resultant influx of people and caps, had allowed the science team to hire a few new hands to help with all of the work.

All that remained were the magically enhanced fusion generators. Sunset and Pia had spent the last few days alternating between brainstorming safe ways to test them, and attempting to come up with a scientific theory as to how and why the magic reacted to radiation the way it did. Unfortunately, progress was a little slower than either would like. Specifically, progress was non-existent.

"What time is it?" Pia asked tiredly.

Sunset grumbled and straightened up so she could check her Pip-Boy. "Nine thirty-two AM, so just over a minute since you last asked."

Pia made a disgusted noise and shoved a clipboard across the table. "This is insane. I've tried every single thing I can think of and I'm getting nothing. None of these equations make any sense whatsoever. How did you used to figure this shit out back in your world?"

"At CHS, I didn't. I never managed to figure out exactly how magic worked back there," Sunset replied. "As for Equestria, things worked differently there. It had what we call a background magical field; a quantity of magic in the water, the earth, even the air itself. It doesn't really make much of an impact on day-to-day life, but it's an essential constant in magical theory and calculations. Trying to figure out magic without it is… How can I put this? … Imagine how much different physics would be if you went to a reality where neutrons didn't exist. A layman wouldn't really understand the issue, but a nuclear physicist would lose their mind."

Pia frowned and scratched her neck absently. "I'm not a nuclear physicist, but I guess the only issue would be atomic mass, so certain elements wouldn't exist. No, hang on, there'd probably be some issue with gluon interaction…" Her frown deepened, then she held her hands up and shook her head. "You know what? I'm not even going to try and wrap my head around it. Okay, so magic study without a magic field is a fucking nightmare, got it."

"Pretty much." Sunset rubbed her eyes, feeling utterly exhausted despite it still being early morning. "And that's before we add the effects of radiation into the mix."

"Ugh, don't remind me." Pia sighed heavily. "I give up. Let's take a break for now and come back to it later."

"Good idea," Sunset said with relief. "I've got training with Danvers later, so I don't want my brain to be too fried for that."

Pia looked at her almost warily. "So… Harkness is still avoiding you?"

Sunset nodded. She had barely even seen him since she had returned his memories. He had even assigned his second in command, Lana Danvers, to take over her training in the gym. The woman wasn't as good a fighter as Harkness, but she was still better than Sunset. Somehow, the fact that Harkness was still looking out for Sunset's well-being despite what had passed between them just made it hurt all the more.

"If you don't mind me asking, what exactly happened between the two of you?" Pia asked tentatively.

"Nothing major," Sunset replied in a toneless voice. "Just a difference of opinion."

Pia looked up as the door opened, then tensed up in her chair. "Um, are you absolutely certain that it wasn't something big?"

Sunset gave her a curious look, glanced over her shoulder to see who had come into the room, then did a double-take when she spotted Harkness in the doorway. She blanched as she spotted the plasma gun clasped in his hands.

"Don't worry, I'm not going to shoot you," Harkness said quickly, correctly interpreting her expression. "I'm actually here to thank you."

"Thank me?" Sunset asked incredulously. "What for?"

Harkness smiled sadly. "For the other day. You could have been a little more subtle about the way you went about it, maybe a bit smarter too, but you did the best you could and, well, I am the one who effectively told you to do it. I've got no one to blame but myself."

Pia looked from one to the other as if she was watching a tennis rally, a look of intense curiosity on her face. "Seriously, what is going on between you two?"

"It's private," Harkness and Sunset replied in unison.

"All right, all right, I'll keep my nose out." Pia glanced at the door. "I can leave you two alone if you want to make up properly on the table."

"Shut up, Pia!" Sunset hissed in a mortified whisper.

Harkness gave her an unamused look. "Enough with the jokes, Pia, I'm just here to give Sunset this." He patted the plasma gun meaningfully.

Sunset stared at him in surprise. "You're giving me that?! But, why? You're in charge of protecting this place, don't you need it?"

"I have other guns," Harkness replied. "Besides, I've heard about all the trouble you've had with the Enclave. If you're going up against power armor, you're going to need a weapon that can penetrate it. This should do the job." He held it up in one hand as he gestured to different parts of it with the other. "I've replaced some of the parts and altered others to make it tougher and easier to maintain, and I've refined the output so each bolt it fires is more powerful without using more ammunition. If you're done here, I'll take you up to the flight deck and show you how to use it."

"Whoa." Sunset glanced at Pia. "Uh, are we done here, or…?"

Pia shrugged. "Fuck it. Sitting here and staring at numbers that make no fucking sense isn't going to help us figure this out. May as well take our minds off it for a bit."

"You'll figure it out," Harkness said bracingly. "I never imagined you'd be able to stop the trees from shooting lightning, but you did. Hell, I thought we were going to have to install a few dozen lightning rods up there."

"Lightning rods wouldn't have helped," Pia supplied. "Magic lightning apparently doesn't earth like normal electricity, it just shoots out into the air randomly."

Sunset gasped as an idea suddenly exploded into her mind. "Holy shit, that's it!"

Pia and Harkness both stared at her in surprise. "What's it?" Pia asked.

Sunset ignored them and rifled through the sheets of paper on the table until she found a blank one, then snatched up a pencil and started scribbling down formulas. "I can't believe I didn't spot this before."

"Spot what before?" Pia pressed.

Sunset paused in her writing for a moment. "How can I explain this in simple terms? You know how light can be treated as both a particle and a wave?"

"No?" Harkness replied.

"It's a physics thing, light behaves as both a particle and a wave," Pia supplied. "Go on, Sunset."

Sunset shrugged and returned to writing as she spoke, "Well, back in Equestria, magic operates under a similar duality; it can be treated either as physical matter or as an energy field, and can behave as both at the same time," Sunset explained. "That's why when two unicorns fire a beam of magic at each other the beams clash, instead of just passing through each other."

"Did she just say unicorns?" Harkness asked quietly.

Sunset nodded jerkily. "Yeah, I was actually born as one, but that's not important. What is important is the fact that magic can't behave like that, in a dual state, without a background magical field to stabilize it. Don't ask why. Starswirl the Bearded spent almost two decades working out the minutiae. It takes years to learn the details of it."

Pia crossed her arms. "Okay… that's fascinating, but how does it apply here?"

Sunset glanced up from her notes just long enough to flash her a grin. "Magic has been behaving exactly like that in this world, too."

"But you just said that magic can only do that when there's a background magical field… wait…" Pia's eyes widened as her mind caught up with her mouth. "You think this world has a background magical field of its own?!"

"I think so," Sunset replied. "In fact, I'm almost positive."

"How can you be so sure?" Pia asked.

"The lightning." Sunset mentally chided herself for not noticing sooner. "The lightning wasn't earthing when it was coming from the trees, so where was it going?"

Pia frowned and snatched up a pencil and paper of her own, quickly wrote down what Sunset had already said, then looked up at her expectantly. "Okay, hit me."

"I'll try and keep this as simple as I can." Sunset took a deep breath before continuing. "Object density affects how the background magical field works, and so does the presence of living creatures, even if they themselves can't use magic. If there wasn't a background magical field, then all of the excess magic from the trees should have all just bled into the ship constantly, instead of blasting out of the tops of them as lightning."

"So most of the magic was going up to the tops of the trees to escape the dense materials and people inside Rivet City, then escaping into the air as lightning when it couldn't travel any further?" Pia asked.

Sunset nodded. "Yeah. Of course, it could just be the case that the rusted metal that makes up the ship is insulating the magic; that has been known to happen sometimes, which would also funnel the magic upwards, but that's where the lightning itself becomes important. If the lightning was just caused by magic escaping the ship and burning itself out, then there should be residue in the air. You'd be able to see it as multicolored dust in the air after each lightning bolt, until it settles back to the ground. The whole damned flight deck would be covered in it if that was the case."

"Is this going to start making sense soon?" Harkness put in.

Sunset glared at him for a second before turning back to the paper. "There's no dust, no residue or aftereffect of any kind, meaning that the magic is diffusing into the atmosphere completely. It wouldn't do that if there wasn't a background magical field in the atmosphere for it to diffuse into."

Pia finished writing it all down, then hummed as she thought. "I don't know, are you sure about this?"

"There must be, it's the only way any of this makes sense," Sunset replied, double-checking the equations she had written down. "If I'm right, then all we need to do to get the affected generators working safely is attach a couple of Diffusers to siphon off excess magic and vent it into the background magical field. If we can gather the right parts, we could probably get one of the generators up and running in about a half hour or so."

Pia gave her an uncertain look. "That sounds all well and good, but what if you're wrong? You said yourself that magic works weirdly in worlds without a background magical field. Maybe the lightning not leaving a residue is just another example of that."

"Yeah, maybe." Sunset gave a satisfied nod and straightened up, crossing her arms. "But I've just tried putting the details of the new magic teleporter room upstairs into one of my old Equestrian formulas for measuring controlled unicorn teleportation, and the math checks out perfectly."

"Really?" Pia hurried around the table to look at the formula. Sunset had to give her a quick layman's explanation of what some of the symbols represented, but after double-checking it thoroughly Pia stepped back and ran a hand through her hair. "Shit, you might actually be onto something. Alright, I think it's worth a shot. All we need to do now is bring it up with the rest of the council so we can put it to a vote."

"That won't be necessary," Harkness cut in. "You only need two out of three votes for it to go ahead. We're both members of the council, that's two votes right there, so you can get straight to work without making us deal with Bannon's whining."

Sunset raised an eyebrow at him. "Are you sure? I don't want to be rude, but did you actually follow most of what we said?"

Harkness shrugged. "You're two of the smartest people I know. If you say that this will work, then I'll believe you. You've earned my trust."

Hearing him say that sent a warm feeling flooding through Sunset's chest. Pia grinned too, clearly happy to have a solution within her grasp, though the fact that she didn't have to deal with Bannon was probably part of it as well. "Sounds good to me," she said brightly. "Alright, Sunnybuns, how do we make those Diffusers?"

It didn't long for Sunset to describe how to make the Diffusers. When she saw Sunset's sketched diagram of them, Pia recognized them as, essentially, miniature Tesla coils; easy enough for her to cobble together. The trickiest part would be directing the magic into the Diffusers and out through the electrodes on top, but Sunset had a few ideas for getting around that.

When Pia was sure about what was needed and how to put it together, she gathered up her notes and smiled at Sunset. "What are we waiting for? Let's get to it!"

Sunset glanced unsurely at Harkness, hoping that she could talk to him in private. He seemed to be thinking along the same lines, as he said, "You go on and get started, Pia. There's something Miss Shimmer and I need to discuss."

Pia looked from one to the other curiously, then shrugged and headed for the door. "Fine, but don't take too long. I'm going to need her help to finish putting all of this together."

The door clicked shut behind Pia, leaving an awkward silence in the room. When she couldn't take it anymore, Sunset cleared her throat and asked tentatively, "So, er, how are you doing?"

"I'm doing alright, all things considered," Harkness replied. "I've been doing a lot of thinking over the last few days, about a lot of different things." Sunset waited patiently as he placed the plasma gun on the table and leaned against it. After a moment he gave a look that was almost wary. "You really don't think it matters that I'm not human?"

"Not in the slightest," Sunset said firmly. "Whether you're an ordinary human or not doesn't make a blind bit of difference as far as I'm concerned. Most of the people I've met in this world have been jerks, losers, or absolute monsters, human or not." She smirked at him. "Besides, where I come from there weren't any humans at all, so who am I to judge?"

Harkness let out a quiet chuckle. "Yes, unicorns you said, wasn't it?"

"Among other things," Sunset replied with a cryptic smile. "If we can ever build a portal home, you can come and see for yourself. Speaking of building things, we'd better go and give Pia a hand before she comes hunting for us."

"Good idea." Harkness stood and picked up the plasma gun again. "Then, once this is all finished, I'll show you how to use this."

Sunset winced as she remembered his offer. "I appreciate it, but if this experiment works I'm going to have to head back to the Citadel immediately. The other girls will need to know. I suppose the Brotherhood should, too," she added as an afterthought.

"Fair enough. In that case I'm sure the Brotherhood will be able to teach you how to use it." Harkness slung the gun over his shoulder and stepped over to the door. "If you used to be a quadruped, I guess that would make doggystyle the most natural way for you. Duly noted."

Sunset cocked her head at him curiously. "What do you mean by doggystyle?"

Harkness stared at her in amazement, then burst out laughing. "Oh man, you're even more sheltered than I thought." He held a hand up in response to Sunset's indignant pout. "That's not a bad thing, it just makes me feel a little guilty about one or two things. Tell you what, if or when I manage to get my head back on straight, I'll be happy to show you. Deal?"

"Deal," Sunset replied. "And I'll hold you to that!"

"I'm sure you will." Harkness chuckled, but his expression quickly turned somber. "Until then, I… I just want some time to try and figure things out. Is that okay?"

Sunset nodded, vaguely understanding what he was hinting at. "Take all the time you need."

Harkness drew in a deep breath, then let it out slowly. "Right, now we really had better go and find Pia."

It didn't take long for Sunset and Harkness to find Pia, and barely half an hour later the three were gathered in the main lab, watching as a pair of technicians finished connecting a pair of Diffusers to their selected generator. The issue of directing the magic had been solved easily enough; they had simply dipped some of the components in a vat full of purple magic that had been siphoned from the trees. They had chosen the purple stuff because Sunset suspected that it was, essentially, a condensed form of Twilight's magic, and given that Twilight's Equestrian counterpart bore the Element of Magic itself, then using her magic was most likely to achieve the desired result.

Sunset felt her heart pounding as the technicians finished with the Diffusers and hooked the generator up to an industrial floor fan. If this experiment worked, it had ramifications for a lot more than the mere generation of electricity. "Okay, are we ready to go?"

Pia bit her lip, clearly nervous, but bravely stepped up to the generator anyway. "Ready when you are."

Sunset waited for the technicians to finish with the fan and get out of the way, then nodded once. "Switch it on."

Her lips moving in a silent prayer, Pia pressed a button on the generator before skipping back several places.

The generator hummed loudly as it powered up. The Diffusers fizzed and popped a few times, a series of purple sparks crackling out from their electrodes, then a faint violet glow emanated from them and the sound settled into a gentle hum. A second later the fan switched on, the blades slowly picking up the pace until they were a circular blur, sending a strong wind blowing towards one of the side rooms.

"It's working," Sunset whispered, hardly daring to believe. She stepped forward and put a hand into the fan's airstream. She couldn't sense the presence of any magic whatsoever. "It's clear, the Diffusers work!"

Pia and the technicians whooped and exchanged high fives as Harkness congratulated them. "I can't believe it, it actually worked!" Pia exclaimed excitedly. "The other scientists are going to freak out when they learn that this world already had a magical field, but we can worry about that another time. For now, we… uh… Sunset? What are you doing?"

Sunset wasn't listening. The moment she was certain that the Diffusers were working, she had darted over to a nearby table and grabbed a clean sheet of paper and a pencil, her hand flying as she made rapid sketches. "This world really has magic… it's weak, but it's enough... I won't even need to adjust the equations all that much… all we need are the right parts, and a way to lock on to the right signature…"

"Would you mind telling us what it is you're muttering about?" Pia asked. "You're starting to creep me out."

Sunset dropped her pencil and looked around at Harkness. He just sighed and smiled wryly. "Back to the Citadel?"

Pia blinked in surprise as Sunset nodded. "The Citadel? Why? Is something wrong?"

"No, nothing's wrong. Something has actually gone very right for a change," Sunset replied quickly. "I need to speak to the rest of the Rainbooms as quickly as possible."

"Can't we at least celebrate a little first?" Pia asked. "What's so important about this background magical field that you have to go running off the second you confirm that it's real?"

Sunset took a deep breath, trying vainly not to get her hopes up, and held up the rough blueprint she had just drawn; a mirror surrounded by a complicated mechanical rig. "I know how to get us home."

---

Rainbow hated hospitals. The Citadel's infirmary wasn't much like any hospital she had been in before, but it still counted. Her, Applejack and Twilight were all sitting around Adam's bed, chatting quietly in an attempt to distract themselves from the fact that Fluttershy, Pinkie and Rarity still weren't back from the Family yet. A message had come in from Arefu two days before, saying that the trio had arrived, and that Vance had agreed to try and help Fluttershy control her hunger, but nothing had been heard since.

"Ah still don't think we should trust that Senator Lily," Applejack said suddenly. "Not in the slightest."

Rainbow rolled her eyes. "Duh, we don't. Elder Lyons said the same thing when I handed over my report and their intel, but he also said we can't just ignore what she tells us."

Twilight hummed thoughtfully. "I think we can trust her."

The other two stared at her in shock. "Are you high again? Or should Ah get the docs to up the meds?" Applejack asked incredulously.

"Think about it," Twilight replied, ignoring the comment. "It may sound childish, but people have been chasing immortality for millennia, even in our own world. With this world's technology, and Equestrian magic, she might even be able to achieve it."

"Why would she even want to be immortal?" Rainbow asked. "Every time you see a movie where someone can live forever, they always want someone to find a way to kill them. They get bored, or they get sick of watching their loved ones get old and die. It just seems pointless."

Twilight shook her head. "That's possible, but those sorts of people are always the ones who see immortality as the end goal. Lily is a scientist. There's a reason she wants to be immortal, and I suspect it's something to do with research. I can't imagine a scientist getting bored of immortality; there's always more to learn, more to discover, more to create. Imagine how far you could push science if you had an eternity to study it in."

Rainbow raised an eyebrow. "Okay, remind me to tell Sunset that we need to keep an eye on the mad scientist over here."

Twilight gave her a flat glare. "I'm not saying we should trust her completely, just that she's probably telling the truth about wanting to keep Project Exodus going, and getting us home. I agree that we should be very, very suspicious of what she wants to do with her immortality, if she ever gets it."

"Meh, Ah guess you're right about that," Applejack said with a shrug. "Not much we can do about it either way. Elder Lyons has the intel, it's up to him what he does with it."

The three lapsed into a bored silence after that. Being stuck in a room with two coma patients, Adam on one side and Sarah Lyons on the other, wasn't exactly conducive to a happy atmosphere, but this was the only place where the girls could be sure that the Scribes wouldn't try to pester them about magic.

"There's something I've been wondering," Rainbow said suddenly, with an odd look at Adam. "People in comas still get food pumped into their stomach through tubes every day, right? So what happens when they need to take a dump?"

"Nice, Rainbow, real nice," Applejack huffed.

Twilight sighed and shook her head. "No, it may be unpleasant, but it's a fair question. Unfortunately, Rainbow, the body's natural processes don't stop just because someone is in a coma, so nurses have to regularly check the patient over and, if necessary, er, clean them up."

Applejack raised an eyebrow. "Hang on, Fluttershy was working as a nurse at Rivet City back when Sunset was in a coma. Does that mean she…?"

"No!" Twilight replied quickly. "Doctor Preston knew that Fluttershy wouldn't be comfortable with looking after a friend like that, so he had someone else take care of it."

"But the only other person who worked at Rivet City's clinic was Doctor Kaplinski." Rainbow grimaced as she put two and two together. "Oh. Uh… let's not tell Sunset."

"I wish you hadn't told me," a voice mumbled petulantly. The girls all gasped as Adam shifted and opened his eyes, looking up at them blearily. "Where's Fluttershy?"

Next Chapter: Chapter 87 - Together Again Estimated time remaining: 25 Hours, 40 Minutes