Undertale belongs to Toby Fox. The Scientist belongs to me. Enjoy!

"Papyrus!" He was about to run to his brother, but a tall human man with short, blond hair dressed in a lab coat stepped down from a large computer on the right with a devious smile on his face. Sans stepped back, watching him.

"Sans, I was wondering when you were going to join us," the middle-aged scientist smirked, casually approaching Papyrus, who was strapped to a chair in the middle of the large room with wires taped to his skull and chest. He was only wearing his jeans and red, Converse shoes.

"Yeah, now that I'm here you can let my brother go," the skeleton coolly stated, watching the man's every move. He felt his magic drain the second he entered the facility and lucky for him, there was no other people here and the signs led him straight to the experimental room.

"Oh, should I? I'm close to my breakthrough about monsters, so why would I give up my research now?"

"'Cuz ya realize you've made a horrible mistake and will regret it if ya don't?" His white eyes followed the scientist, knowing that was not the case. He need to come up with a planed and he knew he should've picked up that metal pipe!

"Huh-uh. Sure."

"Sans," Papyrus whimpered, watching him.

"Hang on, bro," Sans said, glancing around the lab, trying to figure a plan without using magic. Hell, he could just attack the guy with his bare fists, but…

"I'm sure you've noticed this lab is equipped with a machine that drains all magic from any monster who steps into the facility," the scientist announced with a proud smile. "This one," he gestured to Papyrus with a thumb, "kept going on and on how you were going to stop me and save him and all this crap. When I told him that you magic as well as his is drained, there is nothing you can do to stop me!" He laughed.

"Why are you doing this?" Papyrus squeaked, looking at him from the corner of his eye.

"Monsters don't belong on the surface!" he screamed at him, making the skeleton jolt. "Now, I since I've done research," he snapped his gaze to other one, "I learn how HP and magic works. I even tapped into your brother's memory banks!"

Sans blinked.

"I was very skeptical that you were even going to show up, Sans! Let me get this straight," he folded his arms, studying him. "There is a kid who can reset monsters' timelines? And this kid killed each and everyone of you at least ten times– due to the farthest memory I can get– and when it came to your brother, you didn't do anything?" He sadly smiled, shaking his head. "Now that's cruel."

Sans shrank back, locking eyes with his younger brother as guilt crawled through his bones.

"Sans." Papyrus gently began, determined. "I… I know that can't be true. The memories are lies made by him. I know that. I know you wouldn't have…"

With a skeleton grin plastered on his face, Sans slowly lowered his head. "Papyrus…"

"…Sans?"

This was not something he every intended talking about. Especially with his little brother. Maybe Toriel, but not his brother. "I… I don't know what to tell ya, bro."

"What?" he whispered.

"The human, they would reset over and over and over, I don't even know how many times. They would save us and there were times where they just killed us all. They would kill you and I would always try to stop them at the very end, but–"

"You didn't even bother trying to save your brother once?" the man mocked.

Sans forced himself to look at his brother's heartbreaking eyes. "Papyrus… I never wanted you to die."

"You… You knew about the resets?"

He heavily sighed, bowing his head. "Yes…"

"Did you even care that he was going be killed when you knew that he was?" the human demanded.

The skeleton stepped forward, looking him in the eye. "Yes!"

"Liar! If you cared you would have at least tried to save him! I saw those memories! You were never even there. Now why show up now?"

Sans slowly turned to his little brother. His baby brother that he swore to protect since they were kids. What was he going to say? That he got so used to his death that he didn't feel anything? Yes, it still hurt, but he got used to it and even that made him sick as hell to admit that.

"You really are a shitty brother," the scientist murmured. "Either way, I'm sure you're wondering why I have your brother. I only needed one monster for this, but to explain my research, I learned that monsters have their own health bars. They have an HP and can heal and that other monsters can see this if needed. Now, I want to know is what happens to those health bars. Do they die in one shot depends on the weapon? Or," he slipped a hand in his coat pocket and removed a gun, "does it take more than one?"

A chill washed over Sans like a demons was creeping behind.

"Now I get to see what can kill a monster. If you look to the screen on your right, you see a healthy, green bar of 680."

Sans briefly glanced at the screen the sight of his brother's bar.

"Now. Let's see how much damage a monster like him can take." He raised the gun to Papyrus's temple.

"No!" He step forward, tried to summon a Gaster Blaster, then cursed at this scientist. How did he know that there was a generator draining magic before he came in? All he knew was the location of his brother and went alone. Now he was completely useless! "Take me!" The words exploded without thinking and he was not going to stop now. Reality began to sink in. "Use me as your experiments! I used to be a scientist. Research and experiments are what I did best," he lamely smirked. "Let my brother go. I'm stronger than he is. I'm sure I can more useful to you than–"

"But, Sans!" Papyrus shrieked. "You only have one HP! You won't last long at all!"

Sans stared at him like he was about to lecture him when they were kids.

His brother blinked twice, then slowly shrank into his seat as tears welled in his eyes. "No… Sans… You wouldn't…"

"You almost had me there for a minute," the scientist thinly smiled. "But only one?" He clicked his tongue. "That won't do me any good. I need a subject to last long as possible."

A bang rang through Sans's skull as his eyes widened at the sight of a sickening hole in his brother's left temple with a clean hole on other side. He felt heavy, but not enough to cry. What made tears well in his eye sockets was when his brother slowly moved his head and whimpering like a kicked puppy.

"640/680," the monster murmured, looking at the computer screen. "Huh. Far less damage than I thought… Oh. It's actually slowly dropping. Now we know how the gun is against him."

Sans wanted to run to his brother and heal him, but without magic, he was useless. If he even tried to make a move, there would no doubt that a bullet would penetrate him and he would be dust. This was supposed to be their happy ending. To live on the surface with freedom like the humans. Not like this. Not with humans against the monsters as if it was the war centuries ago! Was he that naive? Were they all naive? Why did they all think the humans were going accept them? Underground or on the surface, he was going to watch his brother die, wasn't he? He could die trying to save him, but that would only speed up the process for himself and Papyrus would be suffering alone. He died enough alone. He barely noticed the man approaching him.

"You watched your brother die over and over again," the human coldly mocked, standing a foot taller than Sans. "Now you just stand there and not even try to stop me. Or maybe… you realize that there is nothing you can do with lack of magic." He turned to Papyrus, then back to him with grim curiosity. "You watched your brother die… I wonder what he would do if he watched you die." He took a step back and aimed the gun right between his eyes.

"Sans," Papyrus choked in pain. "No… Please… Not my brother!"

Sans looked passed the gun, passed the man to his baby brother with tears streaking his narrow face. He looked at the man in the eyes and his gaze drifted back to the barrel of the gun. "Close your eyes, little bro," he causally stated. "It'll be easier."

Papyrus began to fidget as if trying to fight out of his restraints, whimpering and sniffling.

Frisk. Kid. Please don't reset. There is no happy ending. The thought of another genocide route made him briefly chuckle. Next time, he'll just let the kid kill him.

The sound of a metal door sliding open made Sans and the human look to the left in the back of the lab to find Toriel and Undyne with Frisk in the lead, bursting inside. Hope and fear jolted him, fearing the worst for them since they can't fight back and hope for that they can outnumber him. Well, Undyne can take him down without magic. However, it was Frisk that sprinted to them with a knife in hand and death in her eye.

"Frisk!" Toriel and Undyne shouted.

The scientist gasped as the teenager was nearing him and turned the gun to her.

Frisk was about to dodge and was ready to deliver a blow, Sans flared with determination and grabbed the gun, aimed at the ceiling as it went off, then punch him in the jaw with a strong fist. Just as the man fell to the ground, Frisk was about to jump him and Sans grabbed her by the waist as he kicked the gun away. "It's okay," he soothed, holding her tight. "It's okay."

She began to cry into his white shirt as the two woman ran to them and Undyne restrained the dazed man with handcuffs.

The skeleton gently pushed the kid away. "Papyrus!" He ran to his brother's side and quickly unbuckled the straps on his wrists and feet. "Papyrus. I-I'm sorry. I–"

"It's okay," he weakly croaked with a sad smile. "I know you care. I never doubted otherwise."

He tightly embraced him. "I thought I was going to lose you," he sobbed.

"I thought I was going to lose you, too," he cried as he gently placed a boney hand on his brother's back.

"You need to get him to Alphys right away," Undyne barked. "She told us where to find you. I'll stay behind and let the authorities know what happened here."

Sans removed the wires from his little brother and gently got him to his feet with Toriel's help and Frisk at his other side and left the shadow of the labratory.

Alphys and Toriel helped tend to Papyrus, who was currently asleep in his own bed with a bandage around his eye and skull. Sans and Frisk were sitting out the backyard of his house, sipping on hot tea that Toriel made as the sun began to set. At least Frisk was. He was relaxing over a bottle of ketchup. Last they heard was that the scientist was arrested by the humans for attempted murder and torture.

Taking a breath, Sans sipped the ketchup. "What were you planning on doing to that guy, anyway?"

"Toriel insisted on me staying at home, but had to find you guys," she murmured, staring at her white teacup. "I know how to use a knife thanks to… Chara… so I decided to help. I'm glad I did because Undyne and Toriel were scared when they felt their magic drain. When I saw you… I had this rage… I didn't want to lose you." She bowed her head. "Not again…"

"Kid. Frisk…" He gently looked at the young girl. "Thank you. I mean it. Thank you."

She simply nodded. "Hm-mm."

He looked ahead of himself. "I, uh, was beginning to wonder if there was actually a happy ending. Our happy ending nearly got us killed." He chuckled.

"Sans?"

"Hm?"

"If it did, I was going to reset and save you all again."

"Ah, kid." He leaned into her chair.

"But, that's only if you or Papyrus are killed by a homicidal– Oh…" She looked away. "Sorry."

He slowly looked at her and took a breath as he placed a hand on her shoulder. "Kid. I know it was Chara."

She looked him with her heart in her brown eyes. "You know I promised to not reset again, right?"

He chuckled. "I know, kid. I know."