A moment later, Percy Jackson and Sans the skeleton stood on stone. It was much warmer here. They were in a stone cave, rock walls surrounding them. Drawing his eyes with a blinding white glow was the barrier. A magnificent glowing wonder. It was like a fire, beautiful and terrible. Standing between him and his home.

Sans broke the silence. "well, we're here. anything else?" He leaned against the rock wall behind him.

Percy hesitated. He glanced up and down the barrier, and then reached out his hand to see what it felt like.

When he noticed something at his feet, he jumped.

"Howdy!" Flowey smiled his big, innocent smile. "Fancy meeting you two here."

Percy drew back, annoyed. "Oh great, it's you again. What are you doing here?"

"Oh, I just wanted to say hello to my two best pals."

Sans interrupted, "you just said it was fancy meeting us here."

"Of course, silly!" Flowey said smoothly. "That's why I came!"

"'course, bud."

The flower frowned. "Are you ALWAYS gonna make that joke?"

Sans grinned, staring Flowey in the face. "'course, bud."

Percy choked down his laughter.

Flowey glared at both of them. "Unbelievable."

Percy spoke up, raising a finger. "I think you mean unbeleafable."

Groaning, Flowey sank back into the earth.

"wait," Sans said, reaching out a hand. "don't leaf!"

Percy burst out laughing.

A moment later, Flowey rose from the ground, towering over them. "You think that's funny?" The extra large flower glowered at Percy. "I'll show you what's funny." The monster pulled out a giant, thorny vine and raised it to strike.

Percy stopped laughing. "Wait, what now?"

Sans shrugged, his glowing eyes and frozen smile revealing nothing. "up to you, kid."

Flowey slammed the vine down at Percy, initiating a Fight. Percy dodged, then looked at his surroundings. Noting the lack of useful water around, he uncapped his pen-sword Riptide.

His opponent feigned shock at the act of aggression. "That's not how you greet your best friend!"

Flowey threw down another big vine where he was standing.

Percy jumped to the side just in time, and then sliced Riptide through the beefy vine, severing it in two.

The monster's insides looked just like any cut flower root: white and plant-y.

The wound barely even seemed to inconvenience Flowey as he pulled more of those vines out of the ground.

The next two came at him from either side—like a high five—and Percy was unable to avoid the large mass of plant that came crashing into him.

Compared to getting hit by Sans, he just felt a single stab of pain as his HP took a drop from 252 to 206. His bruised sides continued to sting, but he'd be alright.

Percy held his sword defensively, closely watching his opponent. He was at a disadvantage here. Flowey was a formidable monster, and he couldn't use his powers, nor could he defeat the flower with jokes and sarcasm, which left him with just his sword.

After ducking a vine that swung his way, he glanced at his companion for a moment and called out, "Sans, I might need some help!"

"you'll do fine. i'm rootin' for ya." Sans leaned casually against the cave wall.

Flowey glared at Sans for his pun. Taking advantage of the monster's distraction, Percy leapt at Flowey and swung Riptide at the base of his body. The celestial bronze blade was able to cut through anything it hit, but before it could land, vines intercepted Percy and hurled him away. 178/252 HP. He clutched his hurt side for a moment but jumped back up.

Flowey pulled back, defensive for once, and slammed his vines at Percy—two again, and harder. Slammed between them, he cried out in pain. 106/252 HP. He could feel at least one broken rib.

Panting, Percy gripped the hilt of his sword, unsure of what to do.

"You could just stop fighting, y'know," Flowey suggested.

He had to defeat Flowey somehow. Either that, or do something to make him stop attacking. If Sans was right, and he was stuck down here, he couldn't very well constantly have a crazy weed at his tail.

Was Flowey right? Should he just give up? Maybe he should just let himself be killed: let the monsters down here take his soul and go free.

But he knew that would hurt his friends and family. If he died, it would break their hearts. He didn't know what he'd do if Annabeth got killed. He loved her so much. They had plans for the future together! At New Rome University!

Or at least they did... Man, he was really gonna miss everyone on the surface if he stayed. And they would miss him as much as if he died. His friends, his mom, even his stepdad Paul. Percy wasn't sure if he was willing to stay Underground for the rest of his life.

But if he left, he would have to kill these monsters' leader and take his soul... He didn't know. He'd promised to Sans that he wouldn't kill another monster, but if he didn't, he'd be here for the rest of his life. No other plans for the future.

...But he could only leave at the cost of another's life, and the hopes of so many.

Percy ran at Flowey, filled with frustration, tears in his eyes. He didn't know what to do.

Flowey caught him off guard, knocking him down with a thorny vine. He grunted. 62/252 HP.

One fight at a time.

He forced himself to calm down. Focus on the fight. That he could control.

He needed to cut the main stem clean off. To do that, he could use a distraction. He ran again at Flowey, but started slower, pretending to be more wounded or tired than he really was. In reality, he was filled to the brim with energy waiting to burst. Suddenly, he yelled.

"Sans! Now!"

The skeleton instantly stood up straight, and hesitated, alert but confused. They had not planned anything.

Flowey instinctively looked at Sans, and his distraction gave Percy the moment he needed to quickly close the distance and swing Riptide all the way through the plant.

The monster looked back at him, shocked. It recovered quickly and tried to grow back, but by then Percy had cut it again.

With the way the creature had grown, it was tall enough that Percy couldn't reach its head, which seemed to be where he'd need to strike. So he cut once more, and then he solidly kicked the monster's top off the rest of its body, leaving cut plant mass in the ground.

The monster struggled more desperately, trying to regrow.

Percy grabbed its now-manageable head and pulled it away from the ground. He couldn't let it grow back its body and gain the upper hand, so he had to finish it off quick.

Not slowing down, Percy swung his sword at the yellow center of the flower.

Suddenly, he heard a voice scream, "It CAN'T be the end!"

Percy froze. The voice came from Flowey. There was genuine panic and fear in that voice. His face was one of terror, eyes wide. He felt a few drops of the creature's sweat against the hand holding his head.

No. He'd made a promise. He had decided not to kill anymore if he could help it, and at least this time, he could help it. He could show Mercy.

That all flashed through Percy's head in an instant.

He shook Flowey to get his attention. "Hey." The flower stopped struggling, and he looked up, wide-eyed. "I'm letting you go," Percy said, sparing him. "We're all gonna have to get along down here. So you leave me alone, and I'll leave you alone."

Flowey's fearful eyes flashed through shock, relief, confusion, and disgust. He didn't say a word as he threw himself from Percy's loose grip and burrowed into the ground.

Percy dropped his sword and sighed. He slumped down to the ground, exhausted.

After a moment, he noticed the stinging ache of bruises and cuts all over his body. Those thorny vines really did a number on him. He looked around for an underground river, then tiredly sighed, remembering that there was no water nearby.

A moment later, Sans was standing over him. Percy had once killed Papyrus in a fit of anger. He remembered the fear he'd felt at what he did, and the pain buried in Sans' eyes when he appeared.

In contrast, when he looked at Sans now, he seemed... proud. Even though he could remember when Percy had killed his brother, right now, he looked freer. Like a burden had been loosed. Seeing that, Percy's own chest loosened, a knot he didn't realize was there being undone.

Emotions welled up from inside him, and all his pent up feelings of relief, shame, sorrow, and exhaustion boiled out of him as tears burst into his eyes. "Thank you," he said. He pulled Sans into a hug. He went stiff at first, surprised. But then he leaned in, relaxing. His bones felt much harder than skin, more rough. But his hug, like any from a human or demigod, radiated warmth.

A moment later, Sans pulled back, and asked, "what for?" For once, Sans was the one confused.

Percy rubbed the tears from his eyes, smiling. "For believing in me. Despite everything. I know you already made a promise, but I still want to thank you for keeping it."

Sans smiled, but then he hesitated, worried. "hey, kid. did you meet that monster in the ruins? the woman?"

Percy nodded. "Toriel. She cared for me."

"toriel..." He seemed to turn the name over in his head. "is she... safe?"

"She's safe," Percy reassured him.

Sans nodded, a little less worried.

"If you want," Percy said, digging in his pockets, "We could actually call her right now." He held up the cell phone he'd gotten from Toriel. He had thrown it in Snowdin Forest's river, but that was before things rewound.

Surprised and anxious, Sans said, "ok."

Percy called Toriel's phone. Dialing...

...

Nobody picked up.

They were both disappointed. Percy tried again. Same result. "Sorry. She didn't pick up."

Sans shrugged. "its fine."

Percy put it away. They sat in silence for a few moments.

Suddenly, Sans said, "if you're not gonna eat that pie, can i have it?"

Surprised, Percy pulled the butterscotch-cinnamon pie out of his pocket. He had completely forgotten about the dessert Toriel had given him before he left the Ruins. "How'd you know about the pie?"

Sans rolled his eyes. "i could smell it the whole time, taunting me." He sighed dramatically.

Percy examined it. Butterscotch Pie - All HP. He looked at his stinging injuries and low HP—62/252—then back at the pie. Butterscotch-cinnamon pie, one slice. Oh, he'd be alright. He could tell Sans was joking about eating it, but who doesn't want pie? Percy ripped the pie into two mostly even pieces and handed one to the again surprised skeleton.

"thanks."

Percy smiled. He ate the butterscotch pie. His HP was half maxed out: 188/252. The aches in his sides lessened, and he felt much better. That was some good pie! Yummy and healthy. He couldn't believe he'd forgotten about it.

Realizing he didn't know how much health Sans had, Percy Checked him as he ate his own part of the pie. Sans: 1 ATK, 1 DEF. The easiest enemy. Can only deal 1 damage.

"What—" Shocked at the low stats, Percy jumped, whacking his head on the rocky wall behind him. "Ow..."

Sans grinned. Percy rubbed his head, and then he said, "You only have 1 ATK and 1 DEF. Do you also have just 1 HP?"

He shrugged. "that's what most people think."

Percy raised his eyebrows expectantly.

"anyway, didn't we come here to look at the barrier?"

Percy blinked. He glanced to his left. How had he completely forgotten about the glowing white elephant in the room? "Yeah."

They sat there for another minute. Looking at the barrier, Sans said, "nice view."

Percy nodded absently.

"so." The skeleton was smiling. "ya really are okay with stayin' down here."

Staring at the light, Percy took a moment to ponder the words. "I am. I'll really miss everyone on the surface," he said longingly, "But I think I am willing to try to stay down here. I just hope they'll be okay without me."

The demigod stood up, and he and Sans stepped up to the solid, glowing wall. Percy looked up, and then sighed, resting his arm against the barrier.

He felt resistance like mud, his arm sinking in. He pulled back, set off-guard by the texture. Sans gave him a weird look at his reaction. Percy reached out to touch the barrier again, curious.

His hand went in. When his elbow went in as well, he glanced back at Sans. "Does this usually happen?" Before getting a response, Percy looked back at the barrier and said, "Who am I kidding, of course it does. Dare I ask why?"

"no."

Percy pulled his arm back out. "Okay."

"i mean, no. this doesn't happen. not unless it's a human who's taken a boss monster's soul."

When Percy looked back, the skeleton's eyes were void.

"No, no!" Percy cried. "I swear I didn't do anything!"

"you killed toriel." Sans stepped back. "you killed her and took her soul, didn't you? you lied to me."

Percy was lost for words, heartbroken. "I... no."

Sans sneered. "no wonder nobody came when you called. all she did was care about you, and you killed her."

Percy shook his head helplessly.

"it doesn't matter what you say. that's the reason you can leave right now."

Percy froze. "I can leave?" A dozen emotions battled in his mind.

"yeah. just go."

He didn't move. He couldn't stand seeing the tired, broken look on Sans' face.

"i said go."

Percy turned back, but he thought for a moment. "Why can I go through the barrier?" he said to himself. "I think I would have remembered taking someone's soul..."

Sans' voice hardened. "kid. leave now, before i break my promise."

Percy's heart broke inside. "But I didn't kill her. I promise."

"your word means nothing anymore." He glared back at Percy, towering over him despite being shorter. "you have the power of a human and a monster soul. you took it from her."

"That's it!" Percy said suddenly. "I got it!"

Sans' baffled expression almost made up for having to see him so upset again.

"I'm a half-blood," Percy said. "I kept forgetting to mention it earlier. I'm only half human. My godly father is the reason why I can manipulate water."

Understanding dawned on the skeleton's face. "your soul is already a mix between a human soul and a monster soul. it can get through on its own."

Percy nodded, smiling. "I'm a half-blood."

Sans looked at the ground, ashamed. "so you really didn't kill her. she is safe." He squeezed his eyes shut, regretful. "i'm sorry i accused you so harshly. i didn't believe you."

Percy set his hands firmly on the skeleton's shoulders. Sans cringed. "Hey. It's okay," Percy said gently. "It's all right now." He felt sympathy for the guy. Sans had been through a lot as well. Right now, Percy just felt so relieved and happy, and he wanted Sans to be able to be happy, too.

Sans gave him a grateful smile. "thanks."

Percy took his hands off his shoulders. He looked back at the barrier.

A moment later, the skeleton said, "so, are ya gonna head back like I said?"

Looking up, Percy responded, "Yeah. It's about time. My friends will be waiting. Just... it feels crazy."

"yeah," Sans said. "take care of yourself, kid. 'cause someone really cares about you."

"Thanks," Percy said. "Hey, could you tell that bunny lady at the inn thanks for me? Give her this, too." He handed him 80 gold pieces. "I may not have had a good night, but because of her, I did have a good day. Though, yeah, it was a whole lot to take in."

"i'll tell her," Sans said.

"Also," Percy pulled the cell phone back out. He looked back at Sans apologetically. "Unfortunately, it's too dangerous for me to take this with me. Could you take it for me? And if she answers or calls, tell her I'm alright."

"will do," Sans said, taking the phone.

"see ya, kid."

"See ya." Percy smiled. After one more moment of hesitation, he stepped through the barrier. It was about a foot thick. Thankfully, when his face was inside it, he could breathe like in air. Or water, but he was pretty sure it'd feel more like air to anyone else.

Ah, it was great to see the sunlight again!

The last time he'd seen the mountain seemed like forever ago. What an amazing sight!

Percy remembered one more thing. He took out the snowman piece from his pocket, which he'd turned into a mini snowman. The snowman he'd met underground wanted to see the world, and the creature had asked Percy to take a piece of him and bring it far away. Well... now it was free. He set it near the edge of the mountain, looking out. If it could see, it would have quite the view.

He may have imagined it, but Percy thought its two pebble eyes looked happier than before, and one of the stick arms looked like it was waving goodbye.

Percy saluted it. "I wish you well. And all the monsters." He sat down next to it for a moment. "I'll tell my friends about what happened down here. Even though part of me is scared to say anything, I'll try to be the monsters' advocate."

Percy froze. He snapped his fingers and said under his breath, "Oh, shoot. My mom is gonna kill me when I get home."

So close. He's even outside. But he's so far because he still has to drive all the way home. That'll take so many minutes... Plenty of time to plan how to not get killed by his family and friends. He gave the Nice Cream he remembered about to his mom and the Faded Ribbon to Annabeth as apology gifts, but the two of them were worried sick, so it wasn't very effective. Ah, the tragedy. Thanks for reading. :)