Sunset rested her hand against the cold glass between herself and Missy, watching her tiny chest rapidly rise and fall with each breath. Alphys's "hyperthaumic" chamber was a dead ringer for a glass coffin, aside from the addition of several machines running tubes into it and taking measurements. A heartbeat monitor beeped away, never letting the tension fall for a moment as Missy's heart continued to race. Alphys had promised the device would help stabilize her, but she wasn't showing any signs of improvement.

A screen on the wall above them had been set to display the ongoing battle, as had many of the others in the lab so that she and the other refugees could watch the heroes battling for their safety. When she would pace to the edge of the room, Sunset could hear the monsters arguing and musing over the situation.

"Lousy humans, they should have just stayed on the surface where they belonged!"

"It doesn't matter! Undyne will stop them! One more human soul and we can break through the barrier, remember?"

She didn't know why he wasn't using the lightsaber she'd given him, but he and Undyne had reached some kind of synchronization. He would weave in and out between her projectiles, ready with a haymaker punch or a powerful kick whenever he could get close enough to the child. Still, the other human didn't seem fazed by the rapidly developing teamwork, often dodging by simple millimeters or allowing one lesser attack to land in exchange for safety from another, more powerful one. Even when Sunset thought there was no way they could survive what was coming, they seemed to find the single safe path through to the other side.

Penn was wearing thinner and thinner. She wasn't sure the monsters could tell, but she'd spent enough time at Beacon to spot a human being's tells for when they were getting weak. His knees were shaking, and he seemed to have broken into a cold sweat. It was obvious that he'd been defaulting to using his arms to defend himself, even without the dual shields he'd used back in Remnant. As a consequence, the skin of his forearms had been slashed and sliced mercilessly, leaving a trail of blood droplets with every step. His movements were growing sluggish, steadily falling behind the pace Undyne was setting. Her magical attacks were relentless, hurling spear after spear at the human, but Sunset could guess that she was growing tired, as well. She was bleeding through her armor in multiple places and huffing loudly for breath. To Sunset, it seemed like the only thing keeping her attacking at such a breakneck pace was sheer force of will.

Sunset jumped slightly as her attention was yanked away from the screen. One of the monsters had come into the room with her and was staring into the chamber with sad eyes. They looked like some kind of bipedal lizard, with no arms and dressed in a yellow-and-brown striped sweater to match their skin.

"I..." Sunset put one hand back on the glass, unable to bring herself to outright confirm or deny anything. "I really hope so. We've been through worse together." Though I can't remember when...

"S-she saved me." Sunset looked again at the kid, seeing their eyes filled with tears as they pressed their forehead against the glass. "This is my fault. If I'd just-"

"Hey." Sunset put a hand on their shoulder and shook her head. "Don't talk like that-"

"But it IS!" the young monster stamped their foot in frustration. "If I hadn't stopped and tried to be tough like Undyne, she and her friend with the pumpkin head wouldn't have had to get between me and the human!" They shook their head, sending more tears dripping in an arc around the floor. "N-now one of them's dead and the other is here..."

"Pumpkin head... you mean Lantern?" Sunset gave their head a comforting pat as she dropped to one knee. "Don't worry about him. He's a... special case. He'll be back. As for Missy..." she took a deep breath, trying to force the words both of them needed to hear to the forefront of her mind. "Missy might be a kid, but I've seen her casually do the impossible every day since we met. She once told me that thinking negatively like this will eat you alive... and she was right. We have to trust her to make it out of this."

Her words seemed to have the intended effect, as the young monster stopped crying and their frown turned upwards. "Y-you really think so?"

Sunset smiled. Somehow, even just saying the hopeful words out loud had given her the ability to believe them. "When this is all over, I'm sure she'll be happy to tell you that we should never have been worried. She'd never leave us THIS close to Halloween!"

She gave the kid one more pat on the shoulder before rising back to her full height and looking back at the chamber. Her eyes widened as she realized a change had taken place. Missy's heart rate was no longer racing, having settled into a much calmer, easy pace, and her breaths were coming slower and deeper. Most noticeable of all, however, was the peaceful smile that occupied her face. The creases and lines in her skin were gone, leaving her totally solid and tangible once more.

For the first time since they'd arrived, she was resting peacefully. Sunset heard footsteps behind her as Doctor Alphys approached the container, still wringing her hands in her typical nervous way but with a smile on her face.

"I-It l-looks like the w-worst is behind us... From here, it's only a m-matter of time before w-we can safely remove her from the chamber!"

"She's going to be okay?" the kid asked, their smile beaming brightly as Alphys nodded.

Sunset smiled and leaned down to press her forehead against the glass. "Sorry it took me so long to remember to believe in you, Missy..."

Sunset's head snapped up, locking on to the source of the familiar voice coming from the corner of the room.

Isis's drone was up on its feet, making shaky and jittery movements as the crystal in its chest flickered between various brightnesses.

"ISIS?" Sunset practically sprinted to the corner, grabbing the drone and raising it to eye level. "Isis, we hear you, you're coming through!"

The drone twitched and jerked in her hands for several seconds before falling completely limp. Sunset felt her hopes fall for a moment as the robot seemed to have gone dead, then soar when the head rose again, this time smoothly.

Sunset couldn't stop herself from pulling the drone in tight and hugging it with all of her strength. "Isis, oh thank the stars you're finally here! We need all of the help we can get!"

Sunset held the drone out again, a touch of worry in her heart. "Isis... are you glitching?"

Sunset heard Alphys gasp behind her. The dinosaur-like scientist ran up, snatching Isis's drone from Sunset's hands to look it in the eye.

Her hands began shaking uncontrollably, her eyes wide as she stepped backwards in shock. Without another word, she ran to a computer terminal on a far wall, setting Isis down and typing furiously.

"We- we thought that we were wrong... we HAD to be wrong..." she muttered as numbers and charts began to flash across the terminal. "We couldn't accept that the numbers were correct, given what they meant!" Sunset stepped up behind her, trying and failing to make sense of the breakneck pace the data was moving at.

"A-a while ago, when Sans and I were both working together, we detected a m-massive timespace anomaly..." The screen finally came to a stop, showing an animation of a single line plotting itself on a moving chart. It began to splinter, splitting into a fractal shape by dividing into two more lines every few seconds. "Everybody knows about the th-theory that timelines split, dividing based on how events p-play out, right?"

Sunset nodded. This was pretty much the founding idea that the "theory" of the multiverse was founded on. "Right... That's pretty simple to follow."

"W-well, because of this anomaly, timelines were behaving... strangely." She tapped a few more keys, and the words "BEGINNING SIMULATION" flashed across the top of the screen. The changes started out small at first, just small flickers on the edges of the forked fractal, but the phenomenon soon moved inwards and became more clear. The lines were flashing, snapping back and forth between new connecting points wildly, tangling together and intersecting in countless places. On the edges, the growth was stunted or even completely dead in places, coming to a stop and leaving the shape haggard and uneven.

"The timelines were changing... interacting. Sometimes they would spring up from nothing, starting something brand new! Others would just... end." She pointed to one of the "dead" sections to illustrate. "And eventually..."

They all watched as the flickering and changing reached back in time, finding its way to the first few iterations. Sunset gasped as an entire section was severed from the roots, shattering and dissolving into nothingness. In a horrifying cascade, more and more timelines vanished from existence until only a few gnarled branches of time were left. The damage refused to stop there, however, as even those few surviving strands blinked out one by one. When the last timeline disappeared, the screen went dark, displaying only the words "ALL TIMELINES ERADICATED."

"E-eventually... everything ends..." She shook her head. "We-we couldn't believe it. Sans- he quit. I don't know what good he thought he could do on his own, maybe the news was just too much for him. I TRIED to find the source, but the closest thing I could find was several points in the underground that seem to be the focus of the splits in the timelines... There's nothing special about the locations, themselves, so it was a dead end. After that, I just assumed that there had to be some kind of fault in the simulation... I guess I was wrong."

The silence that followed was all-encompassing, everyone present clearly horrified at the news. The only one to move for several seconds was Isis, who plugged the end of her tail into the computer.

"But thanks to the barrier, we can't even leave this MOUNTAIN..." Alphys whispered.

"Th-this is heavy..." the monster kid muttered, wide-eyed and clearly still processing the information.

Sunset's mind, meanwhile, was racing, weighing options and possibilities against their resources. "There's a way out."

All eyes were on her as she stepped up, holding out her arm for Isis to climb up onto her shoulder. "This is going to sound unbelievable, but... bear with me. Missy, Penn, Isis, and I didn't just come from the surface... we came here through a portal between universes. If we can break through the barrier that's keeping us underground, we can lead you all to a more stable universe, back the way we came... We could evacuate everyone before the timelines end."

Alphys seemed to have shut down completely, staring at her with her jaw hanging slack. The kid, however, seemed to be taking it slightly better, possibly missing some of the scientific poignancy to her declaration.

"But... the only way to break the barrier is to collect seven human souls, isn't it? Then King Asgore could break it... but we only have six."

"Th-that's true... human souls are the only things with strong enough magic to break the barrier..." Alphys whispered, giving Sunset a forlorn look. "But the only way to separate a soul from a body is... well..."

Sunset swallowed, feeling a chill run down her spine at the implication. On her shoulder, Isis's servos began to grind and growl as she spread her wings protectively.

Alphys held up her hands defensively. "N-no! I never would! B-but it means we don't have a lot of options right now..."

Sunset's brow furrowed with frustration as she tried to think. She felt like she was stumbling around in the dark right now without Penn's explanations: she could only address problems after she'd painfully run straight into them.

It was only when all of them had settled into silent dread that Sunset heard it: the beeping of Missy's heart monitor. Realization dawned on her like the rising sun, and she felt hope growing once more as the obvious solution presented itself.

"What if we could get a huge burst of magic energy for just a few seconds? Earth-shattering amounts of magic focused into a single beam?"

"That... could probably do it, yes, but where would we find that type of power?" Alphys asked as Sunset walked over to Missy's chamber.

"Right here." She patted her hand against the glass. "If we can get the Ghostrick Angel of Mischief up and fighting again, I promise you, she can SHATTER that barrier, and we'll lead everyone here to safety."

Alphys's eyes were wide for a few seconds, equally in awe. After the moment had passed, though, her eyes narrowed with focus and she nodded in affirmation.

"O-okay... then there's no time to waste!" She gestured up to the larger screen still displaying the ongoing battle. "Our friends are holding the human back, but we c-can't take it for granted!" With a flair of her lab coat, she quickly made her way to the chamber and began studying the information on display. "I-I think I might have an idea how w-we could speed up the healing process, but I'm going to need your help, Sunset..."

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"What if we tried to usurp control of the save file? If Flowey could do it at the end of the game, so could you!" Reason suggested.

Flowey had six human souls. It took SIX other souls to out-determination Frisk... do you SEE any other human souls here? Penn countered. He tried to keep himself focused as he ran forward. Undyne's spears followed on either side, zipping past his shoulders and stopping Frisk from dodging to the side. He didn't bother trying to fake them out, opting straight for trying to sweep their legs out from underneath them. As he dropped and swiped with his leading leg, however, Frisk managed to jump up and over it by tucking in their legs, narrowly dodging one of Undyne's spears flying just over their head to intercept.

Don't try to stroke my ego... Penn thought as he pushed himself backwards again, awkwardly rolling backwards as Frisk's counterattack buried the knife blade in the ground where his ankle had been. Still, he'd managed to force them back a few steps, which was more than satisfying.

This was a battle being fought in and for steps. Each side would dip in and out in their attempts to hit each other, their end goal being to take fewer steps backwards than forwards. So far, he and Undyne had managed not to give a single inch that they hadn't taken right back soon after.

But deep down, he knew that this wasn't working. They weren't going to be able to keep this up much longer.

This wasn't like Salem. With Salem, he was being purposefully kept alive. Tortured, yes, but alive. He simply had to NOT give her what she wanted, and not doing things was something of a specialty of his when he was off his meds. It was a waiting game to see whose defense would show a gap first.

Frisk just wanted them both dead. They had to actively try to stay alive while fighting them off, and with the ability to save and reload, Frisk could literally just keep trying over and over again until they got it right.

"Don't SAY that! The moment you start thinking like that, the battle's as good as lost!"

Despite Reason's protests, he could feel the fear beginning to mount as the possible outcomes to this scenario seemed to all start melting away.

Our hand is empty, the field's overwhelmingly outmatched, they know every card in the deck... he glanced at his blood-soaked arms, trying to ignore the stinging and throbbing of his injuries. ...and we're running low on life points. I think...

"HEY! EYES UP, PENN!" Undyne's gravely voice barked. Her arm appeared in front of him as she intercepted Frisk's knife with one of her spears. The two weapons ground and grated against one another for a second before Frisk's blade split the magical construct in two, allowing the blade to rake down the front of Undyne's armor and carve out a large gash across her chest. Her hand grabbed at the injury, but the action seemed to be more reflex than conscious concern as she shot him a glance with her one good eye. "Don't tell me you're losing your nerve NOW, after all this?"

Despite her words, Undyne's entire body shuddered as her balance swayed, nearly falling until she put a gloved hand on his shoulder to hold herself up.

"I... I think we might want to make a tactical retreat..." Penn whispered. "Dying here isn't going to do any-"

"Retreat?" Undyne huffed. "I don't know the meaning of the word." Despite everything, she was still smiling, proudly displaying her numerous fangs. "The only way to face danger is head-on! How else are you gonna ever get strong enough to beat it?" Her smile dimmed and faded as she fixed her gaze back on Frisk. "Besides... retreat where? It's not like we have anywhere to go thanks to the barrier." She pressed down on him for a moment as she forced herself to stand straight again. "Our only option is to win. We can't die. We CAN'T retreat. If you don't think you can DO that, then get out of my way and go find your friends!"

It sounded calloused, but her second meaning was clear as day: she was giving him permission to run. He didn't HAVE to stay, she wouldn't blame him for saving himself.

Even before Reason could make a case in favor of leaving, he already knew his answer: he would never forgive himself if he left her to die.

Well, if we're going all out, guess I might as well toss caution to the wind. If I accidentally cut off my own foot or something, at least I can say I TRIED...

He reached into his pocket, drawing the empty hilt Sunset had given him. Using this meant all but giving up on taking Frisk alive, but... maybe it would buy them more time. More time for him to think, or even more time for Sunset to figure out some kind of solution.

He flicked the switch, causing the bright red blade to emerge with a crackle of energy. He forced himself to step up, standing beside Undyne once again, positioning themselves between the human and everything they cared about.

"If you want me gone, Undyne, you're gonna have to try a little harder than THAT..."

The Multiverse in a Nutshell

by Pennington Inkwell

Determined to the End