Nervous, that's how Sans would describe it. Papyrus had initially reacted to his question with a scream, but to see his brother's emotions switching so rapidly was a sight to behold. One moment he was questioning it, to being excited, then upset. He promised Papyrus he would take him to the Capital today to meet the kid. He figured she would be at school, there was just some hope no one thought it as suspicious or warning.

"remember bro, you can't tell her what i told you about the whole sibling thing"

"OOOHHH, BUT IT'LL BE SO HARD NOT TO BROTHER" Papyrus whined with protest, arms crossed, almost stamping his feet.

"well, she doesn't know and i'd rather those two not be told, cause who knows how'd they would react to the kids they ditched talking to their sister" Sans replied with a shrug. Honestly, he wouldn't past those two to just forbid her from leaving the house or something stupid like that, but then again they seemed as mindful of her as they did with him when he was a tot. They could see the small school for monsters and how it seemed empty now, the kids all gone home. Sitting on the bench, Arial was bouncing up and down in her seat, waiting.

Papyrus waved an arm where she was sitting, as though asking if that was her, Sans nodded to his brother. Papyrus looked utterly giddy when he saw the little skeleton, like he would take off from the ground at moments' notice. Sans couldn't help but chuckle lightly at his brother's reaction. He took a few steps towards the bench.

"hey kid" Arial looked up at the familiar voice. She smiled when she saw it was Sans.

"Hi mister Sans!" she chirped, before she took notice of the taller brother, looking a little intimidated by him at first.

"Uhm..." she started off shyly, seeming to try and sink into her seat.

"don't worry kid, this is my bro papyrus" Sans waved his hand as he spoke, showing the taller skeleton meant no harm.

"Oh! Hi!" she greeted, seeming more comfortable now, but then Papyrus opened his mouth.

"GREETINGS TINY SKELETON" Arial shrank back, shaking a little at the sheer volume of his voice.

"sorry, shoulda warned you paps could be a little loud, but he's not screaming at you" Sans explained, Papyrus never could control that very well.

"O-Oh..." Arial seemed a little shaken up from it, Papyrus looking guilty now.

"SORRY, I CAN TRY AND TALK SOFTER" he said, adjusting his voice to the best of his extent. She offered him a weak smile.

"I-It's okay" She sat up, reaching for her phone.

"so... parents coming to get ya or what?" Sans asked when he saw her reading her phone.

"Uhm... Mama said on here they were going to a con...con..."

"conference?" Sans offered, she nodded.

"And won't come get me till 7" Papyrus blinked, it was only 2, was she supposed to just SIT here for 5 hours? He was starting to see why his brother had an immense disdain towards their birth parents and kept him in the dark about it. When he turned his head he could see Sans thinking, arms crossed.

"so, anyone gonna come let you stay with them or?"

"Nope, it was last minute! So I gotta wait here!" Sans gave a frown to that, but looked to Papyrus.

"hey bro, why don't you go take the kid to the playground? i wanna go see something"

"ALRIGHT BROTHER!" Papyrus seemed ecstatic, his brother going into the school. He held his hand out to Arial.

"COME, SURELY THERE IS SOMETHING YOU WOULD ENJOY TO PLAY" He said, but she began to giggle, taking his hand and followed him.

Sans remembered this daycare and school very well, he had gone to it himself. It changed a little bit since he was here long ago, but the layout was still the same. So when he asked around, it was easy to find the Girl's teacher. He stood in the door way, waiting for her. It was a rabbit monster with glasses, wearing a long skirted dress. She noticed him waiting against the door.

"Oh... Can I help you Hon?" she asked him.

"Yeah, you don't mind me asking about one of your students, Arial Serif?" he asked. She looked at him suspiciously, eyes narrowing. He held a hand up to her.

"i figured i'd get that as a response, look, i'm asking because... well, is mrs. finnigin still working here?" he asked, seeing her look a little surprised.

"She's the school Principle" Sans nodded to that response.

"she here? she can tell you why i'm here" he stated.

"whazzthat sonny?" the two turned, seeing an old fish monster with a walking stick. Sans grinned at her.

"sup mrs. finnigin? still *swimming* i see"

"Sansy boy? That you deary?" the old monster adjusted her glasses.

"in the bones"

"What brings you here boyo?" she asked him.

"well, I wanted to ask about arial serif"

"YOU SEE, THIS PUZZLE WOULD BE DIFFICULT FOR ANY MERE MONSTER OR HUMAN TO SOLVE" Papyrus explained, having made a puzzle blue print with dirt and a stick. Arial looked at it curiously, as though she was trying to figure it out.

"Actually, if someone was to go here, then turn here, press this button, go back and then turn right, there's a button here, and then go around here" she was placing a few stones where she was talking about.

"See? they could get out that way!" she stated, finishing placing the rocks where they could see a path. Papyrus looked it over, almost wanting to scream with some kind of pride.

"SUCH A BRILLIANT MIND LIKE THE GREAT PAPYRUS" He exclaimed, picking her up and hugging her. Arial let out laughter, holding onto him, not even sure why he was so proud, but enjoyed that someone was proud of her. Papyrus was spinning around, just as Sans came to the playground. Finnigin and the Teacher watching Papyrus, a bead of sweat on their heads.

"yo paps" Sans called out to him. Stopping, Papyrus looked at Sans, Arial on his hip.

"The teacher and principle are gonna let us take the kid with us, and will give us a call after they deal with something" he explained, seeing his brother's eyes light up at this. Arial looked a little uncomfortable, not sure her parents would like it.

"they're gonna let your parents know they found someone to keep an eye on you until they come to get you" he told her, seeing her smile now.

"So it's like a sleepover?" she asked him, seeing Sans grin.

"you got it kiddo"

Papyrus would like her no matter what, but the joy he expresses that she knows how Puzzles so well for her age.
Just wait till he introduces her to Undyne