AN: This is a three part story I was originally planning to release all at once. Writing it's taken a lot longer than I expected though, and with finals looming overhead I wanted to at least put the first part out there for people to see just so I can get a feel for if this is something people would even want to read before I completely lose steam. Hopefully I'll have more time to focus on the second and third parts once winter break starts.

I really love stories where Sans gets protective of a bullied/abused Frisk, and in my sadism I started thinking about ways to make that dynamic even better. I latched on to the idea that Sans would probably take personal offense if the abuse was coming from an older brother, and that's where this story comes from. Expect things to get dark, though I'm trying my best to write a villain that isn't one-dimensionally evil.

The first few humans that crossed paths with the monsters at the base of Mt. Ebott were hikers, campers, a lone park ranger. A few screamed, several ran away, thankfully none of them attacked though. That may just have been because no one had a weapon on them except for sticks and rocks. Not that those wouldn't have hurt plenty, but they clearly hadn't been expecting anything like the return of an entire species of creatures. The ranger had reached for a shotgun he kept in the back of his pickup to scare off wild animals, but Frisk was quick to calm him down. Even with a towering skeleton man in front of him laughing manically he seemed hesitant to shoot with the kid potentially in the line of fire. In the end he grabbed his phone instead, calling his superiors, town officials and anyone he could think of that was more likely to be able to handle something like this than someone at his pay grade. Those onlookers that didn't run away immediately slowly warmed to the jovial monsters, a few children even courageously going forward to nervously touch Asgore and Toriel's soft white fur at Frisk's encouragement.

As the ranger called in news of the monsters' return more and more people started showing up, emergency crews, people from both the local and federal government, and more than a few news crews, which Metaton would have loved if he were there. They seemed to want to interview Frisk, all eager to get the scoop on their adventures, but Frisk ducked behind Toriel, happy to make introductions to break the ice between humans and monsters but apparently too shy to talk about themselves in front of so many people. Papyrus was more than willing to step forward in their place, recounting his heroic adventures aided by his good friend the human. The others chimed in often, Sans usually with a goofy pun and Asgore meekly trying to smooth over the parts that cast him as some kind of human hating tyrant.

Some EMT guy offered them all blankets and warm drinks, partially because that seemed to be standard operating procedure for them when it came to dealing with people who weren't physically hurt but they were still called to treat anyway, and partially because if they didn't they'd probably have to leave for some other emergency call, and he really wanted to stick around and see what happened next. Frisk was leaning against Toriel, absently sipping tea as they sat in the back of the ambulance when a police officer pushed through the crowd, leading a frazzled looking woman and a dark haired teen. "Sir, we've located the child's family," the officer reported to his superior as the woman rushed forward.

"Frisk!" she cried out, wrapping her arms tightly around her child. Frisk didn't move at first, shocked by the sudden embrace, but slowly relaxed and gave a small squeeze back. She finally pulled away enough to look them over, smoothing down their fluffy chestnut brown hair and searching for any visible wounds. "I'm sorry, I'm so sorry baby! You aren't hurt are you? Oh god, I'm sorry, I hadn't known about this! Trip hadn't told me you went missing from your camping trip! I had to find out when the police came to tell me they had found you clear on the other side of the mountain! Oh, I knew you were too young to be going out into the woods without me! Please forgive me?" Frisk nodding, taking her hand before reaching out to Toriel.

"Mom. Toriel Mom. Toriel Mom. Mom." They said simply as a way of introduction. The two women looked at each other in surprise, clearly not sure what to make of the other. Clearing her throat Toriel elected to speak up first.

"Ah, yes, that's right. I'm Toriel. I had been looking after Frisk these last few days. Such a dear child. We've gotten very fond of each other in the time we've been together. I take it you are their mo…their mother?" It was hard not to notice the catch in her voice as she reached out to shake the human woman's hand.

"WOWIE FRISK, WHY DID YOU NOT TELL US THAT YOU HAVE SUCH A COOL AND AWESOME BROTHER?" Papyrus asked from the sidelines. The other monsters had quietly gathered around during the display of affection from Frisk's mother. The range of emotions they showed was varied, Undyne and Alphys seemed mostly confused, Asgore looked worried, though it wasn't clear if the concern was for Frisk or for his ex-wife. Papyrus was genuinely excited as he was about everything, and Sans… well Sans was grinning as always but it was hard to tell what that smile meant half the time.

"Erm, how do you know their brother is cool and awesome? He hasn't even said anything yet," Alphys asked, addressing the first of many possible questions that came to mind about all this.

"NYEH HEH HEH! ISN'T IT OBVIOUS DR. ALPHYS? FRISK IS ONE OF THE COOLEST AND MOST AWESOME PEOPLE I KNOW SECOND TO MYSELF. A PERSON LIKE THAT COULD ONLY HAVE A BROTHER THAT IS AT LEAST AS COOL AND AWESOME AS THEM, IF NOT GREATER!" Papyrus explained, clearly proud of his brilliant deduction.

"can't argue with that logic, bro," Sans chimed in with a wink. That got a small smile from Frisk, but caused Papyrus to stamp his foot furiously.

"SANS! OBVIOUSLY WHEN I AM TALKING ABOUT A COOL AND AWESOME BROTHER IT IS IN REFERENCE TO MYSELF! DO NOT TAKE THE COMPLIMENT INTENDED FOR ME FOR YOURSELF!"

"well yeah, but since you're such a cool and awesome person, and i'm your brother, doesn't that mean i have to be at least as cool and awesome as you?" Papyrus gritted his teeth and stamped a few more times, clearly flustered. "is my logic making your head spin now?"

"NYEH HEH HEH! I AM STILL THE MORE COOL AND AWESOME BROTHER HERE! QUIT RIBBING ME!"

Papyrus and Sans' bickering slowly turned into background noise as Frisk's mother waited to speak. "Er… Yes. I'm Susan. And this is my son, Trip." She gestured over to the sullen teen just behind her, a tall and solidly built young man in plaid flannel and dark jeans. "He and Frisk were supposed to be camping together on the western foothills of Mt. Ebott this week, but apparently they were separated and someone didn't think to inform me or the police." The emphasis on the last four words sounded like she was trying to guilt him for being so stupid and reckless, but he seemed to brush off her words dismissively.

"It wasn't like that, I've been showing Frisk my survivalist training and I know those woods as good as our backyard. I was going to find them. Besides, they're fine! Even managed to make some new freaky friends despite practically being a mute."

Susan glared at her son, though whether it was for his inadequate explanation or the offhanded insult it wasn't clear. "You are so grounded, young man. No tv, no computer, no video games, no visiting friends, no car, just home, school, and practice until I say so." Frankly, that actually sounded like a pretty lenient punishment all things considered, but he still growled and fumed like it was some sort of great injustice. He tried to protest, but everything he tried to say was immediately silenced with a stern motherly air.

Still sulking, he started to head towards a where their car was presumably parked, stopping just long enough to call over to Frisk. "Really though, I'm glad you're okay. I wouldn't have wanted to be blamed for something bad happening to you." Frisk's eyes were on the ground, shoulders tense as they didn't even look at him.

Clearing her throat, Susan turned back to Toriel. Her expression was a bit unreadable, exhaustion masking whatever her opinion of the situation was. "I really am very grateful to you for watching over Frisk, and it's clear they have grown very fond of you as well. It seems like you and I have a lot to talk about. Quietly," she directed herself towards Frisk again. "Sweetheart, would it be alright if I have a private conversation with Toriel?" After a moment of thought Frisk gave a solemn nod and let go of Toriel's hand. "Thank you. Don't worry this won't take long, just stay with your friends and we'll be right back."

Frisk stepped away to rejoin the group of monsters, sitting next to Sans. The conversation had turned away from brothers and the arrival of Frisk's family and instead Papyrus and Undyne seemed to be showing off their magic to some reporters. Frisk knew they probably should be paying attention and be ready to rein things in if either of them let the demonstration get out of hand, but somehow they couldn't bring themselves to look away from where their mother and Toriel were talking. It was…good, that neither of them seemed to be getting angry or upset, right? No crying or shouting, no tears or fighting, whatever they were discussing they were doing it in the calm, reasonable manner grown-ups were supposed to. That meant that whatever conclusion they came to would be the right one, because grown-ups always knew the right answer, right?

"hey, kid," Sans speaking up brought Frisk out of their intense concentration. "you know, if you really want to stay with tori, you don't have to leave with your mom just because she came to get you. just speak up about it. i don't think any of us would let her take you if you didn't want to go." Frisk fidgeted a little, staring down at the ground instead of looking at him or at their two mothers. It wouldn't be wrong to do as he says, would it? Their lips barely opened to speak before Sans added, "i certainly wouldn't be okay with it if she's done something bad enough for you to not want to go back with her."

"My mom's not bad!" Frisk protested, whatever they had been about to say gone from their head. "She tries really hard! She's always really busy at work because she takes extra shifts but whenever she's home she always takes care of me." For a second it looked like they were going to say something more, but held back whatever it was they were going to add. That was probably a good thing as Toriel and their mother seemed to have finished their conversation and were heading back over to them.

"My child, it seems that, for now, it would be best for you to return to your family," Toriel explained sadly. "Worry not! We will still see each other frequently and you will be welcome at my home any time you like. But your mother is concerned about giving you up to perfect strangers, and honestly I would feel the same way in her position. This is for the best."

"After the monsters have settled on the surface, if you still really want to live with her we can discuss it then, but for now you belong at home, with me and your brother," Frisk's mother chimed in. She knelt down in front of her child and brushed their bangs out of their eyes gently. "Please tell me you understand, Frisk." Frisk didn't say anything but did nod sullenly. They fought back tears as they gave Toriel a big hug, not letting go for a long time.

When Susan had finally been cleared by the police to take her child home, Sans watched as Frisk's mother led them away. "you sure you're okay with this, tori?"

Toriel wrung her hands together, knuckles probably white under the fur. "Of course it pains me to see them leave, but human and monster relations are too tenuous right now to be fighting over custody if we can't give a good reason why Frisk should stay with us. And Susan really is willing to work with us to let Frisk visit us. We even discussed a schedule for Frisk's duties as human ambassador. She seems like a surprisingly open minded woman, Frisk must have gotten that from her."

"i wonder about that," Sans muttered under his breath. The crowds had finally thinned some as the media circus died down and he could see the humans get into a small car in the parking lot and drive away, Trip in the passenger seat.

It had been about two weeks since the monsters had arrived on the surface and things were going about as well as one could hope for. Although a lot of humans seemed to be scared of monsters, most weren't willing to admit it, and fewer still were insisting on responding with violence. No one wanted to admit that despite the cultural advances of their society, racism could still affect their decision making, even if it was a racism biased against creatures that actually were an entirely different species than the human race. The more reasonable issue for people to focus on was how exactly to incorporate an entire magical society into the mundane one, and what to do about the underground land they came from. The most commonly discussed option was a plan that hybridized the ideas of American Indian reservations and extraterritoriality, granting the monsters dual citizenship of both Home and the surface country they had been living under, with monster laws taking precedence when applicable (assuming there were actual written laws in monster society, as legal conflicts were rare underground and judgements seemed to be based on whatever King Asgore's mood had been at the time). There was also talk about gifting the monsters Mt. Ebott and the surrounding foothills for their own development, but that was more openly controversial. That land was considered a national park, after all, and even if climbing the mountain was considered a stupid and dangerous thing from which one would never return, robbing the entire country of their right to it was something even the most sympathetic human politicians hesitated on.

A more thorough discussion of the possible repercussions of this proposal was scheduled that day, with Ambassador Frisk attending as they had every big monster/human meeting. True to Susan's word, she had been amazingly accommodating with her child's new busy schedule. Every morning she dropped Frisk off with Toriel on her way to work, and they'd chat about what was planned for the day. If their meetings would be over after Susan got off work she would come pick them up at the end of the day, but more often she'd be working late, so Frisk would usually beg to stay over for dinner with the monsters before someone else would take them home.

Today was the first time that there had been a change to that. The big meeting hadn't been scheduled until the afternoon, and as it was the only thing Frisk had to attend that day, they hadn't gotten a ride with their mother. They had said they could get over to the meeting hall on their own, but Sans decided to swing over to their house and give them a ride himself. He'd just acquired his own set of wheels, a speedy little moped, and even if he didn't have all the right paperwork for it he wanted this chance to show it off. And possibly to get a closer look at what Frisk's home life was really like.

Something about Trip had been bugging him at the back of his mind for days. Sans had to admit that maybe he just felt a bit biased against the guy based on his first impression of him. It irked him that this guy didn't seem all that concerned about Frisk. The kid went missing for days while on his watch and all he cared about was getting blamed for it? There was so much wrong with that he didn't know where to begin. He couldn't imagine being that uncaring towards Papyrus. But then again, he and Paps only had each other, while it looked like Trip and Frisk could at least rely on their mother. Maybe he just didn't care for the responsibility that came with being put in charge of a small child. Sans could almost sympathize with that. That wasn't really an excuse for being so cold towards the kid though.

Trying to put those concerns at the back of his mind, Sans pulled up to the house. It was a simple two-story house in a suburban neighborhood, a little larger than his and Papyrus' place back in Snowdin, with some flowering bushes out front. There was a jeep parked in the driveway, maybe Trip's when he wasn't being grounded? He should probably be prepared to talk with him as Sans rang the doorbell. What Sans hadn't been expecting when the door opened was for a teenaged girl to be standing there. She let out a small shriek, gaping at the skeleton man in front of her. "whoops, sorry, guess i got the wrong house," he started to apologize when someone called out from inside the house.

"What's all the screaming a- Woah! Hey you're Frisk's friend right? I remember you from Mt. Ebott," Trip came into view from behind the girl, working his way around her to stand in the doorframe. "I guess we haven't really been introduced, but I'm Trip and this is my girlfriend Kelly."

"sans. sans skeleton." He said, not bothering with a handshake as he kept his hands in his pockets. It wouldn't really be funny to pull the whoopie cushion trick on two people at once, and besides, he didn't exactly feel like shaking this guy's hand in the first place.

"So you're really just a skeleton, huh?" Trip asked, poking Sans' shoulder curiously. Sans stood his ground, not letting the gentle nudge move him as he stood there with his hands in the pockets of his big blue jacket. Trip poked him a few more times, practically shoving him as the force slowly increased. Finally he pushed hard enough that Sans had to give in and he reached up to swat him away with his bony hand. That surprised Trip and he stared for a moment at the skeletal hand. Then his mouth curved into a grin. "Man, that is so, fucking, METAL! I can't believe the twerp hangs out with something this cool!" He clapped Sans' shoulder one last time in good spirits and guided him inside the house..

"So you're here to take Frisk to go do that weird monster ambassador stuff, right? That's perfect. Means Kelly and I don't have to stick around here and play babysitter all afternoon. FRISK!" He shouted loudly towards the staircase that lead to the upper story, probably loud enough to be heard everywhere in the house. "Get out here, Ambassadork! You've got company!" He turned his head to the girlfriend, who had moved away from the door after Trip showed up. "Babe, go get your stuff. We'll go hang out with Reggie and the guys."

Sans would have raised an eyebrow if he had them. Wasn't this guy supposed to be grounded? Even if Frisk was out of the house, that shouldn't make it okay for him to be going out as well. For that matter what was this girlfriend doing here? He remembered the rules Frisk's mom outlined. Apparently having her come over was some sort of loophole to the 'no visiting friends' part of his grounding.

Sans saw Frisk arrive at the top of the stairs. They seemed confused by the announcement of a visitor, but immediately brightened when they saw Sans and waved enthusiastically. Sans waved back before Frisk scampered back upstairs, presumably to grab some things from their room.

"yeah, we've actually got to get going. those human officials are such windbags, they take up so much time talking but they get mad if the meeting starts late. hey, just in case something happens, why don't you give me your number so i can call you to let you know if we'll be late or something? i'll put it on my skel-phone."

"Sure, man, sure," Trip answered, apparently not noticing the pun at all as he pulled out his phone. "Good call, man. That's probably the responsible thing to do or whatever so Mom'll be happy about it. I told her it was too important for me to be able to contact people in emergencies for her to take my phone away too, now I can prove it. Thanks a lot." They read their numbers off to each other when Kelly returned carrying her purse. "Alright, Frisk has a key, so remember to lock up the house, Mom's working a double shift today so she won't be back until after midnight. Catch you later, man!"

With that the two teens were out of the house. Sans saw them get into a silver sedan parked on the street, Kelly in the driver's side while Trip rode shotgun. Guess that's one way to get around not being allowed to drive. For a moment he was alone in the strange house, and he took in the surroundings. All together it looked like a fairly normal home. A living room here by the front entrance, doors leading to a kitchen and dining room in the far corner. Clean but lived in, and all of the furniture he could see looked like it was at least five years old.

There was a collection of framed photographs hanging in the entrance, right over a small table covered in mail and old magazines. The photographs were mostly of Frisk and Trip at various ages. School photographs, Trip in a scout uniform showing off an impressive collection of badges, Frisk making a silly face as they dangled from a set of monkey bars. There was one of the two of them dressed up for some kind of play, Trip wearing robes and a fake beard that made him look like a king and Frisk wearing horns and long dangling ears that suggested they were supposed to be some kind of animal (Goat maybe?). There were a few other photographs too, older ones. One of Frisk's mother, dressed all in white and beaming next to a man who bore a strong resemblance to Trip. The man and a very young Trip out at a lake, proudly showing off the tiny fish they caught. All four of them having a portrait taken together, Frisk so tiny in their mother's lap Sans doubted they even understood that a picture was being taken. There was a scuffling sound and Sans turned to see that Frisk had returned, holding the backpack they carried all their monster ambassador papers in. "your dad?" Sans asked, pointing at the man in the photographs.

Frisk nodded. "He's gone," they whispered solemnly, not giving any more explanation. Sans wasn't going to press that issue. If there was more to that story that they wanted to talk about they would have said it.

Frisk crossed the room and took Sans' hand. They led him further into the house. "what's up frisk? got something to show me?" Sans asked. Frisk nodded again. They were smiling a little now, excited by whatever it was they wanted to share. "is it something that's going tibia-mazing?" he added. Frisk's smile got bigger and they nodded even more enthusiastically. "then lead the way, kid."

Frisk led them towards the kitchen, past what looked like a laundry room, and out a back door into the yard. There was camping equipment lined up along the back wall of the house, a shed with a pile of assorted pieces of wood from some half-finished project leaning against it, and…a line of skulls perched on the back fence. Animal skulls, hollow eyes staring out at them. Sans knew a thing or two about bones, and he could recognize what each of them had once been. Deer, sheep, cow, goat. Looking at them just sitting there was downright morbid. "what the hell is that? some kind of sick joke?"

Frisk's eyes went wide as they realized what he was looking at. Apparently that wasn't what they meant to show him. "A project Trip did for biology last year. He keeps them around because he thinks they look cool." From the way they were squirming under his gaze Sans thought that Frisk probably didn't feel the same way.

"well i don't find it very humerus," Sans muttered, forcing himself to look away from the empty eye sockets. "come on kid, what was it you wanted to show me?"

Frisk walked over to the pile of scrap wood by the shed and knelt down. They patted their knees and called out softly. After a moment a black nose poked out from a gap in the wood, followed by the head and body. The small dog's white fur was amazingly pristine despite being out in the elements who knows how long. It barked playfully at Frisk. "I found them here the other night," they explained, smiling as they patted the dog's head. "Is it one of the ones from Snowdin?"

Sans thought for a moment. "all the members of the snowdin canine unit are accounted for. it might just be a regular dog," he said noncommittally. Of course, there was at least one other dog from the underground he could think of that wasn't exactly a member of the sentries. But if this was the same dog -which he couldn't say for sure that it was- he wasn't going to be the one to reveal it. That mutt always seemed to have its own agenda, and if that had something to do with hanging out at Frisk's house that was fine by him. It would be nice to know he wasn't the only one watching out for the human.

"I might ask my mom if I can keep it then, if it sticks around. She likes animals." Frisk said as they stroked the dog some more. Suddenly the dog leapt up, grabbed Frisk's backpack and carried it to the other side of the yard. Sans thought about using blue magic to stop it –that backpack had important stuff in it after all- but before he could act the dog stopped and shook its head ferociously. The backpack opened and papers spilled out all over the yard.

Sans and Frisk started collecting the fallen pages when Sans realized the papers he was picking up were blank. In fact, looking out at the mess of loose leaf pages, all of the papers were blank. "i think you're missing a few things from your notes," he said as he showed the blank documents to Frisk. "like words."

Frisk looked shocked before their face crumpled into understanding. "It must have been Trip. He must have swapped out the stuff in my backpack as a prank." They gave a resigned sigh and stuffed the blank papers back into the bag. "Hopefully he'll give them back this time."

Sans didn't like the way Frisk said that. How often had had Trip done something like this before? And how often did they get them back? All the humans seemed to think Frisk was little more than a figurehead, didn't take their attempts to play an active part in paving the way for monster-human relations seriously. Trip stealing important documents just before a big meeting made Frisk look like the irresponsible child their naysayers called them out to be. "it's getting close to the meeting time. come on, if we hurry we might be able to get new copies of those boring documents and reports before it starts."

Frisk nodded and started over to the house, still clutching the backpack full of useless papers to their chest. Together they walked back through the house out to the front door. Frisk pulled out a keyring with several different sized keys on it and began to lock up the house. They walked over to Sans' new moped and Sans held out a spare helmet. Sans was still thinking about Trip's prank. He didn't really want his type of humor to be associated with that kind of cruelty. "hey, kid. if you don't want me to pull any more pranks on you because that guy thinks stuff like this is funny then-," Sans didn't finish his sentence as Frisk shook their head no.

"I like your pranks. They're silly, not mean," they explained as they put on the offered helmet. It didn't fit right, and they realized something was inside it.

"i was going to say 'maybe you should wait to put on your helmet'," Sans finished with a wink as Frisk pulled the helmet off. A pair of hotdogs, nestled in paper wrappers and still steaming hot, balanced on top of their head. Sans grabbed one of them and took a big bite, polishing off almost half of it. Frisk reached up carefully to take the other one. They didn't know how it wasn't squished from being carried around in a moped helmet, or how it could still be warm sitting out for so long. Just part of what made Sans Sans. If he didn't do stuff like this it would just be non-sans. Frisk giggled as they realized the pun they just thought of, which caused Sans to look at them questioningly. "i know my jokes are hilarious, but if you aren't going to eat that i'll finish it." Frisk shook their head vigorously and moved to shield their hotdog from him before taking a small bite. The taste was…questionable. They decided to store the rest of it for later. "all right then, but for real though, we'd better get going. don't want to be late for getting bored to death." Nodding, Frisk put the 'dog-less helmet back on and Sans revved the engine on his little bike before zipping off down the road.