"Does your monster haaaave..." said Papyrus, slowly, as he stared at the rows and rows of monster portraits all set up in a grid, "Horns?"

Gaster, a pleasant smile on his face, shook his head, "No."

"Darn!" cried Papyrus as he flicked down three portraits, leaving almost the entire cast of Underground Guess Who's generic monster denizens still a possibility.

Gaster, sitting up straight and tall at his end of the table, tapped his chin with a finger, before his smile widened, and he said, "Does your monster have three or more eyes?"

"Yes!" said Papyrus excitedly, and then began to make sounds of anguish once Gaster's graceful fingertips pushed down nearly the entire board, culling out everyone with only one or two eyes, and leaving him with five possibilities. "No! How did you know?"

"It was simply a safe guess, no matter the answer I would have been able to turn over several possibilities."

"Hmmmm," said Papyrus, beginning to sweat as he faced off against his most dangerous opponent yet, "Hmmmmmmm!"

Sans had been watching from across the room for a while, killing time before dinner was ready. Their father had taken to cooking again, and a quiche, well-adjusted and taken care of with good prospects for the future, was in the oven. It had been something of an overnight transformation ever since that night in the lab when Papyrus had disappeared into the multiverse. All of a sudden Gaster seemed to spend no time at all in the lab, and spent all day of every day playing games with Papyrus, cracking jokes with Sans, cooking dinner, and tucking them in at night. Gaster was better than his word. They were the perfect family.

Sans worried slightly about the state of the barrier, or about his father's position as the Royal Scientist, but he understood what was happening. They almost lost Papyrus thanks to that machine downstairs, and Gaster blamed himself. It made sense to take a break for a while to spend time with his sons, and Sans had to admit it was the happiest he had been in a long time.

There was a beep from the kitchen timer, and Gaster stood, holding up a finger. "We must pause the game, Papyrus. I must not neglect the Quiche. It is a grave responsibility."

"Ok Daddy," said Papyrus.

"I'll make sure the little bonehead doesn't cheat," Sans said, shooting a smug grin Papyrus' way.

"I don't cheat! I never cheat! The Great Papyrus is always an honorable opponent!"

"Whatever you say, Kiddo."

Gaster gave a chuckle at his kids antics before he turned and bustled off to the kitchen. The smell of delicious egg pie wafted through the room a moment later as the kitchen timer was turned off.

There was a moment of silence, while Papyrus stared hard at the backs of Gaster's Guess Who board, trying to divine who his person was, and Sans stared at Papyrus. After a second. Papyrus sat back and calmed down.

"Sans," he said, quietly.

"Yeah kiddo?"

"I feel... I feel bad."

Sans straightened himself out, frowning as he looked up at his brother. "Bad? Why?"

"Because... Because Daddy is a hero, right? But we aren't doing anything except playing games and being together. Doesn't Daddy need to help the king break the barrier?"

Sans' frown curled back up into a smile. "He was scared. He thought we were gone forever. I think he's just happy that we're here with him."

"But... but he's not just our Daddy, is he?" said Papyrus, "Being a hero means... means you gotta know who needs help the most, right? Doesn't the king – doesn't everyone need help more than we do? Daddy needs to break the barrier."

Sans had to take a moment to really take in what his brother had said. "That's very mature of you to say."

Papyrus couldn't help but smile a little, but he was still looking down at the table. Sans gave a little sigh, sinking down in his chair, relaxing. He thought that maybe Papyrus was thinking back – forward, maybe - to when he grows up to be some kind of hero in Snowdin, wearing that ridiculous thrown-together costume. Sans could see that Papyrus wanted to end up there, but wanted his father to be worthy of the same thing as well.

"And here I thought all you wanted was for Dad to play with you more."

"Well, I still want that!" cried Papyrus, "That's... that's why I feel bad. I want one thing for me, and I want another thing for him, but I know they can't both happen, can they?"

"Sometimes you can't get everything you want, kiddo," said Sans, "Something's gotta give."

"Yeah?"

"The question is are you gonna be shellfish or not?"

"D-don't you mean Selfish?"

"Nah, Papyrus. All you have to do is ask yourself, 'Water you going to do about it?'"

"Sans stop."

"Do you Sea what I mean?"

"Sans no."

"Maybe I need to be more Pacific."

"Ahhhhhh!"

"What's all this screaming about?" said Gaster as he came back into the room.

"Daddy! Sans is making ocean puns. Make him stop!"

Gaster smirked, "Why were you talking about the Ocean?"

"We weren't!" cried Papyrus, "He just started and he wouldn't stop."

"Well, bad form Sans," said Gaster, "It's not clever if you just bring up the Ocean out of nowhere."

"Sorry Dad," said Sans, "The pun just came to mind."

"It's quite all right," said Gaster, smiling, "And don't worry about it anymore, Papyrus, I'm sure he was only squidding."

Papyrus could not take it anymore. He fell out of his chair, onto the ground, and writhed about, suffering. He covered his face with his scarf to cover up the fact that he was smiling.

"You're all awful!"

Sans and Gaster both laughed merrily, and soon, even Papyrus joined in on their mirth, between calling them terrible people. Soon, however, Sans felt hunger pangs, which reminded him of his father's responsibility.

"Dad, is the Quiche finished?" said Sans, "I'm starving."

"Quiche?" said Gaster, his smile fading into confusion, "What Quiche?"

Sans paused, staring at his Dad, before he laughed, "Very funny, Dad. Didn't you just take the Quiche out of the oven?"

Gaster's face shifted from confusion, to a sudden horror. He stood with a hurried 'excuse me' and rushed back out of the room. Papyrus was still writhing about, and did not notice anything was wrong, but Sans knew better. Their father was fastidious, and took his responsibilities seriously. He would not have begun making a Quiche lightly. Sans stood and followed.

Gaster stood in the kitchen. He was wearing a white, frilly apron with a small, tasteful skull embroidered on the breast, and a pair of red oven mitts. He was holding the Quiche. The center was fine, but the edges were burned. He had left the Quiche for too long. He looked devastated.

"Dad?"

"S-Sans! Oh, I'm sorry, I must have lost track of the time," said Gaster, "I... I should be ashamed of myself. I ruined the Quiche."

Sans took a tentative step forward, "Dad. You were in here for something like ten minutes. What happened?"

"I... Nothing happened. It simply slipped my mind."

"That's not right," said Sans, "You're always so responsible. You never ruined a Quiche before."

"Everyone makes mistakes, Sans."

"You forgot," muttered Sans, realizing what was bothering him, "You forgot all about it. How could you forget about something you went into the kitchen to check on a few minutes ago?"

"I..." but Gaster said nothing more.

Sans' mind was racing. The pieces were falling together in his mind.

"Dad," he said, "Did you just come back from time traveling?"

Gaster's silence told him all he needed to know. Silently, he put the Quiche on the counter and took off his oven mitts, laying them gently beside his failed responsibility. He leaned against the counter, sighing deeply, and finally turned his head to look his son in the eye.

"Yes," said Gaster, "I remember now. The Quiche needed a few more minutes in the oven, and the game with Papyrus was on hold, so I thought I could... step out for a while."

"Step out?" asked Sans, "Where did you go? Have you done this before?"

"I do it sometimes, yes," admitted Gaster, "I still have to finish my research, but I don't want to miss a moment with either of you. This way I can have it both ways. I travel a few minutes into the future, and use that timeline to further my research non-stop, then return. It's like I never left, and I can bring my notes back with me. I have made leaps and bounds in exploring the boundaries of time!"

Sans' face fell. Usually he had been there whenever his father had made such leaps and bounds in his research.

"Why didn't you tell me?" asked Sans, "You could have brought me with you. I could have helped."

"But you've been helping. Just the other day you... Oh."

Sans furrowed his brow. "That wasn't me. That was another Sans from another timeline."

"Yes, I suppose it was," said Gaster, "I just thought with the traumatic experience you and Papyrus had, perhaps you wouldn't have wanted to go again."

"Dad, I love that you're giving Papyrus and me so much attention, but I still want to help you break the barrier."

Gaster smiled and shook his head, still staring at the Quiche in incredulity, "Yes. You're right. Oh my, what are we going to do for dinner now? I feel like such a klutz."

"Well, there's all that dry spaghetti Papyrus made me buy. That's quick, and Papyrus will love it."

"Yes," said Gaster, "That makes sense. In the morning we can find this Quiche a good home. The responsibility was too great for me. Will you help me, Sans?"

Sans shrugged his shoulders, "If you promise after you put Papyrus to bed, we can go down into the lab. I want to see what you're working on."

Gaster laughed, smiling, "Yes. Fine. Let's get started."

–

That night, after Papyrus was cruising whilst he was snoozing, Gaster was good on his word, and led Sans down into the laboratory. Gaster seemed nervous as he did, wringing his expressive hands together. Sans tried to be nonchalant about it, but his father's mood made him wonder just what he was doing down here.

As they finished descending the stairs and the time machine came into view, Gaster's nerves seemed to get the better of him. He cleared his throat, standing up rail straight, before he began to talk, as much with his hands as with his words.

"Well, Sans. I should preface this by saying that... that what you see here cannot leave this room, do you understand?"

"Well, okay," said Sans, "Why?"

"You'll just have to trust me."

Gaster breathed deeply, before he walked over to a work table. Various tools were strewn about, and Sans noticed that a set of strange, bleached skulls of some creature were stacked all around a cylindrical object hidden beneath a sheet. Sans knew of those devices. They were invented by his father, a power conduit for monster SOULs, to focus and strengthen the power of their bullets. As far as Sans knew, they were his father's weapons of choice, but he had not needed to touch them since the end of the war.

"Dad," said Sans, "What's under the sheet?"

"The fruits of my research. Very promising, but..." Gaster trailed off, clearly nervous. He shook his head, and finally, gently lifted the sheet off of the object.

Sans' eyes went wide. Beneath the sheet, there was a glass case, vacuum sealed on the top and bottom by flat metal devices. Within, floating in the middle, and pulsing lightly in a haunting rhythm, was a heart, scarlet red, casting a light glow across the room. The sight of it made Sans uneasy.

"D-Dad," said Sans, suddenly afraid, "What's that?"

"That, Sans, is a human SOUL."

Sans twisted his neck to stared at his father suddenly. It was insane! It was impossible! Sans couldn't believe it. He shook his head, and turned back to stare anew at the pulsing of the SOUL.

"A SOUL..." muttered Sans. "H-how did you get it?"

"I must repeat myself, Sans. You must not allow news of this to leave this room, you understand? King Dreemur cannot know about this."

The desperation in his father's voice was not lost upon Sans, "Dad? What did you do?"

Gaster tried to smile. He began to pace around the room, touching different tools and surfaces to calm himself as he tried to find a way to explain.

"The truth is, Sans, it was Papyrus who inspired me. That scarf he brought back? I've analyzed it so much. It's perfectly identical to the one you bought for him weeks ago, except it is exactly twelve years older. A perfect replica of an object that already exists. It seems impossible... it should be impossible! It violates the laws of the universe, but even so, somehow Papyrus was able to bring an object back with him, smuggled into our timeline, interacting freely with itself, and automatically corrected for by the Paradox Engine."

"Uh huh?"

"Well, I got to thinking about what else I could try to replicate. I started small. I went minutes into the past to try to bring minor things back with me. Pencils, copies of my notes, things like that. It was perfectly fine – simple even! No ill effects, no matter how much I did it. If I could do that with objects, I started to wonder if I could do it with... with other things."

"You mean SOULs?"

"Precisely!" said Gaster, turning towards Sans and, in an unguarded moment, smiling a bit too widely to be altogether sane, "I knew where I could get a SOUL. It was years ago, before you were born. There was a human who fell into the underground."

"A human?"

"The King and Queen adopted them. He and Prince Asriel became inseparable, but... the child was troubled. They fell ill one day. It was... suspicious. King Dreemur denied it, but the symptoms pointed clearly to suicide."

Sans was silent. He could find nothing to say.

"What's more – and this is the part I'm sure you have learned from your history lessons – consumed with grief, prince Asriel absorbed the human's SOUL and crossed the barrier to deliver the human's body to their home town. When he came back he had sustained horrible injury, and died soon after. The SOUL was lost... until now."

"Now you have it," said Sans, "How."

"I simply..." began Gaster, but there was a catch in his throat. He hesitated, unable to meet his son's gaze. Eventually, he collected himself. "I simply traveled to a time before the child took poison, and... acquired it."

"Acquired...?" said Sans, his eyes widening, "You mean you... You killed the kid?"

"We need SOULs, Sans," said Gaster, "We need seven. That is the only way to break the barrier."

"But you... that's murder! How could you...?"

"It isn't like that, Sans!" said Gaster, "Look around you. Has anything changed? Events still played out as usual. The human is dead, the prince is dead, and the Dreemurs are still grieving. This is the real timeline. Those people in other timelines? You can't think of them as real, Sans. They are only illusions. They aren't us."

"Okay, fine, they aren't us," said Sans, "But they're still real! You said so. The other timelines are all possibilities that could have been where we ended up."

"Think about it Sans. Killing the child in that other timeline did not affect this timeline in any way, except that I can bring back the child's SOUL. He can be of use here."

"But... but no! This isn't right. All of this just for one SOUL?"

"But it isn't just one SOUL, Sans!" cried Gaster, trying desperately to explain, "Think! Every time I travel back, there is a new human child – a new SOUL – a new timeline! If I keep going back, I can keep collecting them. This one is just the first of many," said Gaster, pride sneaking into his voice as his hands clenched, the answer so close, "This is a troubled child who kills themselves anyway. They literally throw their SOUL away. I... We are simply picking up what they didn't want in the first place. We are saving them from themselves. Do you understand?"

For the first time, Sans did not understand what his father was saying. He didn't want to understand. He wanted to close his eyes, run away, and forget everything he had heard here. However, he simply stood, staring at the human SOUL.

Gaster continued, "Only six more, and we will be able to destroy the barrier. We will be free, and the cost is less than nothing."

"But what happens to the timelines where the kid is dead before he's supposed to die?"

"Irrelevant. I wish you would understand, Sans. All that matters is our research. We are on the brink! This is what we have been working towards this whole time."

"This sounds dangerous."

Gaster rushed towards his son, falling to his knees and clapping the young skeleton on the shoulders, squeezing the bones so hard Sans was almost afraid they might break.

"Science cannot balk in the face of danger, Sans! I know I taught you that much."

"You also taught us that Science was for helping people. Papyrus looks up to you. He wants you to keep going, to help make the world a better place for monsters, but... but this?"

"... I... I thought you would understand, Sans."

"I do! I do understand! I really do. I know you want to help free us, but... but I've seen the future too, you know. I saw the Gaster from the future. Something happened. He isn't himself. What if this is what leads to that?"

"You can't compare me to a version of me that doesn't exist yet. Any number of variables could have caused that. Observing that future could have irreversibly changed it."

"But we can't know for sure. Shouldn't we do more research? Find out for sure? Find out whether this... whether this is really the only option?"

"I have been researching this for years, Sans! Years!"

"Years? But... but... that's not right. It's only been a few weeks since you finished the machine."

Gaster did not listen. He simply went on, "There is no other way. DETERMINATION from a human SOUL is the only force strong enough to destroy the barrier, but I cannot travel anywhere with too much DETERMINATION. The human child is the only point in time where there is only a single human in the underground. I've explored the rest of the timeline. Other humans fall in the future but... but there is something else in the way, another being of DETERMINATION that I cannot detect. They tip the balance too much, and I'm unable to travel into that future."

Sans couldn't speak for a moment. He was in shock. This plan of his father's, it was murder... but was it really? If you kill someone, and then travel to a timeline where that person is no longer dead, is that murder? Sans began to wrap his mind around the concept. It was attractive. The Sans in the timeline he and his brother had visited was dead, after all, and Papyrus was the one who killed him. Wasn't it better to believe in the reality where is brother wasn't a murderer? Perhaps those people really were illusions.

But even thinking in that way didn't stop Sans from remembering the numb horror of death, feeling his limbs turn to dust, and feeling his own SOUL on the verge of breaking. How could he condone killing anyone, when dying felt like that?

"I want to help you, Dad," said Sans, "but... but I can't."

"Sans..." said Gaster, tightening his grip, "Please."

Sans shrugged off his father's hands and pulled away, unable to meet his father's gaze. He turned away and walked on quickly, eager to get away from here, and to get away from the red light of the human SOUL.

"I have to go say goodnight to Papyrus," Sans said, suddenly, "You... you do whatever you want. I won't stop you."

"You won't tell anyone, will you?" said Gaster, "You promised."

"Yeah. I did," he answered, regretting it already.

–

A kiss on the forehead woke Papyrus from his slumber. He rubbed his eyes and struggled to open them, and saw Sans looking down at him, tears in his eyes.

"Sans?" said Papyrus, "What's going on?"

"Nothing," said Sans, "Goodnight kiddo. It's just a bad dream."

"O-oh. Okay."

Sans ran a hand over the top of Papyrus' skull, and the younger skeleton shifted himself, rolling over and closing his eyes again. Sans watched his little brother fall back to sleep through blurred vision, and wiped his face on the side of his hand.