For every action, there is a reaction. It is theorized that each action and reaction creates a new timeline, dimension, universe, whatever you want to call it. Some of these new dimensions contain very minor changes. Thus, an infinite number of inconsequentially different timelines exist. However, an equally infinite number of timelines containing huge differences exist. Yet another equally infinite number of timelines were exactly the same as their neighbors since the beginning of time, until one seemingly small change occurred; "the beginning of time" being respective to the timeline in question, that is.

The human we know as Frisk exists in many different timelines. The name applies to boys, girls, those in between, adults, kids, babies, monsters, humans… The possibilities are endless.

The Frisk of Dimension MAC-174 is very similar to one of her other counterparts. One small change, however, can make a huge difference in the grand scheme of things.

The human child's footsteps echoed as she traversed the final corridor of the CORE, towards the elevator which would allow her to finally leave Hotland and enter the king's castle, whereupon she would cross the barrier and leave the Underground. Somehow. Frisk hadn't exactly worked out all of the details yet, but just kind of winging it had worked wonders for her thus far, so she were sure she would find a way. She had to. The thought of approaching the king, and asking him nicely to just let her through, as Papyrus suggested at the beginning of her journey, filled her with DETERMINATION.

Really, her biggest concern was Sans. At the end of her last run, Sans had… Not been helpful. What should have been her easiest challenge wound up being the challenge that cost her a full RESET. It's not like Frisk didn't feel BAD about the things she did. But at the time, she felt like she had to do it. The first one was an accident. She didn't know her own strength, and Toriel paid for it… Dearly.

Then there was that nagging voice in the back of her head. A voice that sounded like her own, yet somehow much, much colder. And older, as old as a child's voice could sound. It told her that, so long as Frisk did what the voice said, she would be fine. Frisk was told that Papyrus would betray her, so, she did what she had to do. After all, in this world, it's kill or be killed, right? After that, things got easier. It became easier to kill once she wasn't as emotionally attached.

After the RESET—as Frisk discovered, her newfound time traveling ability required her to adhere to strict rules such as where and when he could and couldn't travel to—Frisk found that her actions had no consequences. So, she thought, let's just ignore that little voice in my head from now on. After all, what was the worst that could happen? If things went wrong, she could just RESET again.

Once she learned that, yes, Toriel could be saved, no, Papyrus was not a threat to her, and no, Monster Kid was not free EXP, Frisk honestly felt a little stupid. She let the voice in her head control her. She hated herself for it.

Well, more so than she already did. But Frisk didn't like to think about what led her to Mt. Ebott in the first place.

So, yes, she was slightly apprehensive at meeting Sans in the Judgement Hall again. She remembered all too well the feeling of bone tearing flesh, blaster searing muscle. And that was when she were LV 19. As Frisk had not killed anybody this time, she never gained any EXP, she never gained LOVE, and her HP remained at twenty, where it was at the start of her adventure. She, truthfully, had NO idea how she were going to deal with Sans. But she'd find a way. She'd have to.

Still, though, she hoped that, if she was destined to fight Sans, he'd go a bit easier on her this time. Maybe she can spare him since he knows she hasn't killed anyone… In this timeline, at least.

Man, was Frisk glad that Sans couldn't remember the previous timelines. When she left the Ruins, she slipped up and greeted Sans before he told her to turn around and even called him by name before his formal introduction. He didn't seem to think much of it, but Frisk knew better than to take chances with the pun-loving skeleton. She's been very careful ever since.

Despite that, she was receptive to the idea that, perhaps Sans was destined to end her journey right here. At least, if she were going to die, she died knowing she hadn't let herself be lied to again. Her entire second journey through the Underground, Frisk didn't harm a SOUL. Never again will Frisk allow herself to be fooled by the likes of a tiny, whining voice.

It was at this point that Alphys, the Underground's Royal Scientist who'd been helping her through Hotland, decided to speak up. Alphys followed her through the remainder of the CORE after Mettaton's batteries ran out and hadn't spoken up until this point.

"S-so," she began with her usual stutter, "you're about to meet ASGORE h-huh?" Frisk simply nodded in response. "You must be…" She seemed like she was holding onto something she didn't want to say. Frisk stopped and turned to face her. "Y-you must be…" Frisk tilted her head, confused. "Pr… Pretty excited about all that, huh? You'll f-f-finally… You'll finally get to go home!" Alphys was avoiding eye contact. Frisk thought that was weird, but she just chalked it up to Alphys being Alphys. No biggie. She kept walking. Alphys stopped again after a few feet, but Frisk didn't notice. "W-wait!" Frisk turned around again, startled.

"Is something wrong, Alphys? Are you okay?" Frisk asked, genuine concern for her new friend beginning to show.

"F-fine, I just…" She looked away. "I mean, um… I… I was just going to, um… Say goodbye, and…" Alphy's eyelids lowered. She still refused to make eye contact with Frisk.

Frisk scratched the back of her neck. First Toriel, now Alphys… Was leaving the Underground really such a good idea? It seemed she was just hurting the same people she'd wanted to protect by leaving. When she left the Ruins, Frisk simply chalked up Toriel's apprehension to the fact that she very probably thought she'd be killed once she left, as so many other human children before her had. She didn't think for a moment that she actually just didn't want her to leave her behind. She weren't used to being cared about. Now here she was, with Alphys, who seemed equally saddened by the prospect of Frisk leaving the Underground.

Frisk approached Alphys, who simply stared at her own feet. "Hey, you know, I, uh, still have this cell phone. I've been calling a couple of other friends with it for a while now. If you'd like to, once I'm out on the surface, you can call me all you want. It'll be like I never left!"

Alphys didn't look comforted. "Yeah… Once you're on the surface."

"Listen, Alphys, I know that it feels like I'm just up and leaving you. But, like, I can't stay here forever," Frisk reasoned.

"O-oh, of course not!" Alphys quickly responded. "After all, you probably have family up there, and… Stuff."

Now it was Frisk's turn to avoid eye contact. "Yeah… Family…"

"B-but… That's not why I'm acting so… Funny."

"Oh?"

"...human. I… I can't take this anymore." Alphys swallowed hard. Whatever she was about to tell her, Frisk could tell it was heavy. "I… I lied to you."

Frisk closed her eyes. "Alphys, if this is about your role in the obstacles I've encountered thus far, I promise I'm not mad. If I'm being honest, Mettaton's antics were actually kind of fun and I'm glad you were able to make yourself feel like a star! You're my friend, and-"

"N-no," she interrupted. "It's… It's not that either. It's… It's about the barrier." Her voice began to break. "I told you that, with your powerful SOUL, you could cross the barrier. I wasn't being entirely truthful. A human soul isn't strong enough to cross the barrier alone."

Frisk's studied her intently. Her face was unchanging. "So you're saying we've gotta find another way across, right?"

Alphys sighed. "It takes at LEAST a human soul."

"Which I have."

"A human soul, and…" she swallowed again. "And… And a monster soul." She looked back up at Frisk, whose DETERMINATION levels dropped significantly upon hearing that. "If you want to go home…"

"No..."

"You'll have to take his soul. You'll have to kill ASGORE. ...I'm sorry." With that, Alphys turned to leave.

Angry at nobody in particular, Frisk let out a groan and punched the wall, swearing under her breath once the pain shot through her arm. Startled, Alphys turned and looked at her again.

"A-are you okay-?"

"I thought-!"

Alphys looked like she could cry. "I know, I should have told you sooner, I just-!"

Frisk fell to the floor, completely undetermined. "I thought I had done everything right this time."

Alphys tilted her head, confused. "This time…?"

Frisk brought her knees up to her body, resting her chin on them. Tears flowed freely from her eyes. "I don't want to kill again…"

Alphys' eyes widened. "A-again?" She had no idea she'd been leading a murderer through Hotland. She could have sworn she saw her spare every monster in her way. Not that she was really watching at all times, but… Then she realized. The one fight she hadn't been watching. "Undyne…"

This child in front of her… Had killed Undyne. The horrifying realization finally set in. "You… Killed Undyne?"

Frisk's eyes widened. She looked up at the reptilian above her. "No! No, I didn't. Undyne is fine. She's with her friend, Papyrus, in Snowdin right now. I haven't harmed anyone."

Alphys sighed in relief, although she definitely would call Undyne after this to make sure Frisk was telling the truth—but she felt like she could trust her, for some reason. "So, why then, did you say you…?"

Frisk, realizing her slip up, stood up. "Nothing. I mean, I didn't. What I meant to say was I don't want to kill Asgore. I'm going to go up that elevator, march through New Home, walk past the judgement hall, and-"

Alphys interrupted. "Okay, now, hold on, there's a new bit of information. How do you know the layout of Asgore's castle? You've never been in there." This was as confused as Alphys has ever been. She knew for a fact this was the human's first time passing through Hotland. So how, then, did she seem to know what was coming? "Come to think of it," she added, "you seemed to know EXACTLY where you were going after you came into the CORE. You knew what rooms to avoid, which path to take… You ignored my instructions like you knew the layout had changed."

She's adding two and two together, said the voice in Frisk's head. You know what to do. Indeed, Frisk knew what to do. She stood up, sighing. Alphys came clean with her. It was time she came clean with Alphys. That's… Not what I meant, the voice said, slightly disappointed. Frisk chuckled internally. In response, the voice blew imaginary raspberries. Alphys was a scientist. If anybody needed to know about this strange ability, it was her. She just hoped she wouldn't think she was totally crazy.

"Alphys," Frisk began, "I haven't been entirely truthful with you either." She explained the power to her, leaving out most of the murder-y details. What it does. What she can do with it. Its limitations. Alphys' eyes were wide the entire time. When she'd finished explaining it, she looked like she'd grown two or three heads right in front of her.

"T-time travel?" She asked for clarification. Frisk nodded. "That's… That's…" Alphys' dorky grin from earlier returned in full force. "That's amazing! It's just like this anime I watch, about this girl who's stuck in a time loop, and they keep reliving the same day, and she has to find a way to stop an alien invasion beforetheendofthedayandthere'sthisguyshelikesandsheusesthelooptolearnlotsabouthimandalsoshe'sinabandbutbecauseofthisalieninvasionshenevergetsanythingdonebeforetheearthexplodesbutonedayshefindsoneoftheiragentsandwhoopsIalmostspoiledthebigtwistwhereherloveinterestisworkingwiththe-"

"Alphys," Frisk snapped her out of it. "Focus."

Alphys blushed slightly. "Uh, right. So, um… Y-you've… Killed Asgore before?"

Frisk shook her head. "I didn't get to his throne room the first time."

Alphys frowned. "So then who…?" Frisk's face grew sad. I guess she has to learn about the other thing, too, she thought. It wasn't a matter of who did Frisk kill. It was a matter of who DIDN'T she kill. Before she could answer, however, Alphys shook her head. "I guess it doesn't matter. Whoever it was, you clearly felt bad enough about it to… Do things over?" Frisk nodded.

"So… You're sure there's no other way to get past the barrier?"

Alphys shook her head. "No. A being can only cross the barrier if they possess both a human and a monster soul. The barrier can be broken with the use of seven human souls, but…"

"...I would have to die."

"Exactly."

The corridor was silent for a bit. Finally, Frisk spoke up. "So… Why haven't you killed me, then?"

Alphys' eyes widened. "What are you-?"

"I mean… If you killed me, you could bring my soul to Asgore, he becomes a god and breaks the barrier, and the surface is taken back from humanity. All of your problems are very easily solved with my death."

Alphys searched for the right answer. "I don't know," she admitted, finally. It was true. Frisk's continued existence was an obstacle that kept the monsters underground. And yet, she couldn't bring herself to think of her like that. Frisk was her friend, not a hurdle to be jumped over.

More silence. Frisk knew what to do. Deep down, she knew it was the right thing to do. If Sans was going to kill her in the next room anyway, then…

Frisk looked back up at Alphys. "I won't fight Asgore."

Alphys breathed a sigh of relief. "K-kid, you have no idea how happy I am to hear you say that. I know it's not your home, but… The Underground isn't so bad, once you get used to it. I-if you'd like, I mean, you can stay at my lab, if you don't have any other place to stay, although-"

"I'm not staying here, either."

"...what?"

What? the voice asked. Frisk definitely knew what she had to do. She had to do the right thing. She had to do what was best for everyone around her, even if it wasn't in her own best interests. "I'm going to let Asgore take my soul." She looked Alphys in the eyes. "You're going to be free." With that, Frisk entered the elevator.

As the doors were closing, Alphys wedged her foot in them, preventing the elevator from leaving. "H-hang on! You can't be serious!" she exclaimed. "You can't- Y-you can't just tell me what you just told me and expect me to just forget about it and go back to my lab like I didn't hear anything!"

"Well, that's awkward, because that's exactly what I'm expecting you to do," replied Frisk. Alphys rolled her eyes. Clearly this human had been hanging out with Sans. Alphys briefly wondered what he was doing these days before snapping out of it and turning her attention back to the human in front of her.

"I can't let you go up there." Alphys had made up her mind. She was going to take the human back to her lab, by force if necessary, then call Undyne and figure out what to do about this situation.

"Assertive!" replied Frisk in a somewhat colder voice. "You really think you can keep me here?" Alphys took a step back, careful to leave her right foot wedged in the door. She could have sworn she saw a red glint in the human's normally green eyes, but as soon as she blinked, the human shook her head and seemed to have returned to normal. "Uh, sorry. That was rude of me," the child responded. Child? Alphys wasn't sure. She looked to be about twelve or thirteen, but the tone she took up just now sounded like someone who was much older and much, much more tired. In any case, mental age aside, she were physically too young to be going on a suicide mission.

Alphys crossed her arms. "You're coming back to my lab." Normally, Alphys would've backed down ages ago, but she couldn't afford to this time. A child's life was on the line. The king had killed six. Alphys was going to save one, and any others that came after them. The scientist was only twenty-three years old and already she'd ruined enough lives to last a lifetime. She was going to make up for that, starting now.

Frisk shook her head. "This is something I have to do. The needs of the many outweigh the needs of the few."

Alphys was annoyed, now. "If you go up there and hand your soul to Asgore, we're going to war. Do you understand that? It's not just your life on the line, here." The child's life was her primary concern, but she wasn't about to tell her that. "If you die here, you'll be the first of millions." The human looked surprised. She hadn't thought of that. Good. She was swaying her. "Tell me, human, where's the closest city once you leave the mountain?"

"That'd be Denver."

"And how many people live in Denver?"

The human looked like she had to think about it. "I dunno. Half a million? It's not a very big city."

Alphys' eyes widened. "Whoa, wait, half a million isn't 'big'? Just how many humans are up there? And what's a 'big' city like?"

"There are around seven billion people on Earth, about five million live in Colorado—the state where Mt. Ebott is located—three million live in the metropolitan area immediately surrounding Denver, and a big city like New York has around eight million people," the human explained.

Seven. Billion. Humans?! Alphys' mind was racing. She truthfully had no the planet could even hold that many people, and the Underground only had a few thousand monsters. "W-well if you give Asgore your soul, you can consider Denver's entire population obliterated in a day. Colorado in a week. The world in mere months. That's how powerful he would become."

"I can't say we don't have it coming," Frisk replied dryly. "But… You're right. It certainly would be a shame if my death were the first of billions."

Satisfied, Alphys nodded. "I'm glad you see it my way, human!"

Frisk put her finger on her chin. Just how was she going to convince Asgore not to just straight-up kill a bunch of humans once she gave him her soul? Years of hatred can't be solved with one generous act, that was for sure. This truly was a pickle.

With a sigh of defeat, Frisk pushed the button, opening the doors all the way, and stepped out of the elevator. "Ok. Obviously, my plan needs more planning. I still one hundred percent intend to give my soul to Asgore—" Alphys was about to protest, but Frisk continued anyway. "—but I can't give it to him without knowing for sure that he won't use it to start World War III."

Eh?! There have been two global wars already?! thought a suddenly alarmed Alphys. She wondered how the humans hadn't killed each other themselves by now.

"So for now, I'm gonna stick around the Underground. It's not like I have anywhere else to be anyway. You win. I'll come back to your lab with you."

Alphys smiled. "Kid, you have no idea how relieved I am right now. I've been screwing things up my entire life. Saving you might be the first thing I've done right since… Ever."

"Can I ask a favor, though, Alphys?"

Alphys nodded. "Anything."

Frisk looked away. "Please don't tell anyone else what I told you today. About the time travel. About the things I did in another time. ESPECIALLY not Undyne."

Alphys was used to keeping secrets, but for once she was keeping somebody else's secret. Somehow, that was relieving. She put her claws on Frisk's shoulder. "Human," she began, "you have my word. Not a word of any of this will leave the two of us. It'll just be our little secret, uh… What's your name? I never got it."

"Frisk. Just call me Frisk."

Alphys smiled. "Frisk. I promise you, from here on out, your past doesn't matter to me. The future is what we should be focusing on."

The two walked back to Alphys' lab, Mettaton and his dead batteries in tow.

The future, Alphys thought. I like the sound of that. For once, she was looking forward to the future.