The Gaster's took you in and you got your own bed in Sans and Papyrus room. You were treated like family by Sans and Grillby and Gaster wasn't bad to you either. He just wasn't around to often. Sans explained that his dad's job was really important and required a lot of his attention in order to break the barrier without the use of human souls. You understood. "hey [Y/N]..?" You looked at Sans from your spot playing with an animal farm. "Yeah?" He snorted at your choice of toys. "i was wondering if you would like to drop my bro off and we could start that tunnel we were talking about?" You immediately gathered the toys and brought them upstairs and to the toy box. Then you scrambled downstairs with Papyrus in your arms. Sans just laughed and rolled his eyelights and got his coat and shoes on. He took Pap so you could get dressed as well. Then you made sure the baby himself was swaddled and ready, and left for Grillby's. You felt eyes on you as you walked through town with Sans. He took your hand in a form of comfort.

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You started the project at the side of Sans house, first making the igloo. You both worked all day and well into dusk, only stopping once for lunch. You were still working on it when Gaster returned home. "What are you two doing? And where's your brother?" Gaster asked Sans, who was packing the generously big pile of snow. "making a tunnel through snowdin inn and at grillby's." He replied distractedly. "how you doing in there, think that's good enough?" Gaster saw your head poke out of inside of the igloo. "Almost. Then you can help me with the tunnel." You disappeared back inside. He chuckled and shook his head. "ok shortie, whatever you say." He replied with a chuckle. "When I return with your brother, I would like you both to come in for the night, understood?" Gaster asked. "yes dad."
"Ok Mr. Gaster!" You called from inside the igloo. Gaster headed to Grillby's, listening to the whispers. "Did you see Sans with that human?"
"They look close."
"He was holding her hand."
"Sans isn't a very social child. He'd rather be with that eccentric father of his. She must be good, right?"
"Shh! The Dr is right there!" Gaster smirked. Things were going better than expected.

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The days stretched on as you and Sans continued on the tunnel. You had to be at least half through the town by now. There was no hope of Gaster retrieving either of you now unless he went down himself. It was a rather tight fit for an adult though. Soon enough he simply sent his hands down to retrieve you. The first time made Sans laugh and he teased you for the rest of the night. You were digging when the magic hand tugged at your sleeve. You shooed it off, but it persisted until you looked down and screamed. A hand detached form someone's body was pretty scary. Sans jumped, then laughed. "d-don’t worry! it's just my dad's magic!" Still, he continued to wheeze as you both crawled down the tunnel and you were thoroughly embarrassed. "What happened? I heard your scream from up here." Gaster asked with a grin that said all. You pouted, walking to the house. "You guys are bullies!" Sans and Gaster laughed. "c'mon [N/N]! ya love me!"
"No I don't!" You yelled back as you went into the house. "You better apologize, she may not forgive you." Gaster teased. "oh shut up!" Sans waved him off and followed your path to home.

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You did forgive Sans and the project continued. Monsters actually started to interact with you both when you at Grillby's. "The Child of Snowdin" is what they called you. The sweetheart human that the Snowdin monsters would protect. It HAD been three months now. So they'd definitely had time to get used to you and get to know you. The bunnies offered you a free room and breakfast which you politely declined and you got a discount on Nice Cream. Everyone was just all around friendly. Even if you and Sans accidentally broke Grillby's jukebox in a dancing challenge.. Oops. "[Y/N]?!" You and Sans had been digging upwards and had literally just popped out of the snow beside Snowed Inn. It scared the crap out of one of the rabbit children and the kids mother immediately came to investigate. "Hi miss." You pulled yourself out of the tunnel, Sans following suit. "it's complete!!!!" His arms pumped up in the air. "We have to make the igloo around it." You pointed out. Sans groaned and faceplated the snow. "It won't take more than a couple more days." He sat up. "ok, let's finish this."

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And you did. You successfully made a tunnel from Snowed Inn to Sans house. A shortcut if someone didn't want to interact with others, which was rare, but it happened. Today you woke up to Sans shaking the crap outta you. "itssssssssssss giftmasssssssss!!!!!! wake uuuuuuuuupppppp!!!!!" He yelled in your face, to which you retorted by literally kicking him off the bed. "What's Giftmas?" You asked in tired annoyance. "it's a snowdin holiday where the monsters all give each other gifts, and santa is comin! we gotta go!" Sans grabbed your hand and dragged you down the stairs while you tried to wake yourself excited and get in the 'Giftmas' spirit. You assumed Giftmas was the monster version of Christmas since Santa was brought up. Did Santa have the magic necessary to get through the barrier? You supposed so, he WAS Santa after all. Gaster followed you both out with Papyrus in his arms as the monsters of Snowdin passed out and opened gifts.

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Santa was different from what you remembered in the past. He still wore the same red suit, but he had white fur and blonde hair and was clearly shocked to see you when you ran up to him and gave him a hug. You didn't notice as the adults went tense and silent. "Thank you for visiting the monsters, Santa! They are very kind and deserve kindness in return!" You told him, looking up at him. Santa crouched down. "Of course, young human. Who might you be?" Asgore noticed the shift in his people's mood immediately. "That is [Y/N]." Gaster stepped in. "I've been tending to her after Sans found and befriended her in Snowdin Forest." Asgore nodded in understanding. The warning note in Gaster's voice had been received. The girl was off limits. Asgore would have to talk to Gaster later, but for now, he had a holiday to attend to.