"If train A leaves the station travelling at 50 kilometres per hour, and train B leaves a station two hundred miles away travelling at 25 kilometres per hour, when will the two trains pass each other?" Artie blinks at the question and lets out a low groan, pushing the textbook away with one foot as they flop back on the carpet. You don't try to catch them this time. The carpet in your bedroom at your brothers' house is thick and soft enough, with its cheerful pattern of tiny white dogs chasing bones around a blue background, that it absorbs most of the impact from Artie's fall. "I hate human textbooks. Why are they all so boring?"

You pull the textbook closer and frown at the question. "I don't know. I don't remember them being this bad. And they don't tell us enough to answer the question. Is Sans on either of those trains? It'll be late if he is. That always happens. Except when he's early."

The floor shakes as a loud banging echoes through the house, and you lunge to catch the pet rock before it topples from your nightstand. You're pretty sure that was Sans' sole contribution to your decor, but he made sure you knew it was there, in case you ever got lonely.

Artie looks up from their sprawl on the rug as you put the rock back more securely on the nightstand. "What was that?"

"Dunno. Undyne's over, so it's either a cooking lesson, or the three of them are fighting over dish duty again-" Your eyes widen as you feel something skip just behind your breastbone, and you throw yourself on top of your friend, pinning them to the ground. Before they can protest, a blue bone shoots up through the floor, phasing through you as it rockets skyward and passes through the roof. "Okay, definitely dishes. Sorry for squashing you."

"Nah, it's okay," Artie says. You push yourself off of them, but don't bother offering to help them 're perfectly capable of doing it themself, and offering to help with something so little just makes them insulted. They roll back to a sitting position far more easily than you do, and reach out with a foot to close the textbook. "Want to switch to science?"

You brighten at that. Science is a lot more fun than math, and the school board is a lot less insistent that you learn human ways of doing it. "Sure! It's gravity, right?" You bounce to your feet, grinning. "I think we should do an experiment. Outside."

Artie grins and stands as well, giving you an affectionate headbump on your shoulder. "Great idea. There's a ton of snow out there just waiting for an experiment. Hang on, just let me get my arms."

Artie bounds over to the corner of your room to where a tangled pile of metal waits, and kicks it toward the carpet, nudging it into place with their feet until two long metal arms stretch out from either side of the sturdy back brace. Moving to stand in front of it, Artie twitches their tail out of the way and falls backward onto it with an ease born of long practice. As soon as they thump into it, the arms twitch to life, and they reach out to fasten the chest straps and lock the arm rig into place. Well, the right arm does. The left arm is twisted at a funny angle and just flops a couple of times, and Artie rolls their eyes. "Hey, can you help?"

Shaking your head, you grab Artie's left hand and give it a good, strong yank. With a squeak of protest, the arm snaps back into proper alignment, and after a few jerky stutters, begins to swing at Artie's side. "You know," you point out as Artie picks up their backpack and opens your door. "Alphys might be right about you being too hard on your arms."

Artie just looks at you. "Frisk, they're made of metal," they explain, as though it's the most obvious thing in the world. "Metal is tough. Now come on, before the snow melts."

"It's February. I don't think it's going anywhere." But they're already running down the stairs, and you hurry to keep up.

At the bottom of the landing, you have to dodge quickly as Undyne and Papyrus roll past. Papyrus is putting up a good fight, but Undyne clearly has the upper hand. "Admit it, Papyrus! The noogie of friendship trumps all other attacks of amiability!"

"NEVER! IT'S NOT NEARLY AS ENTERTAINING AS THE TICKLE FIGHT OF CORDIAL AFFECTION - OW - AND IT HURTS A LOT MORE!"

"Of course it hurts! That's how you know I care! You are filled with the burning passion of my attachment!"

"I AM FILLED WITH A HEADACHE!"

Sidestepping the two adults - well, more or less - currently locked in affectionate combat on your floor, you grab your boots and lean against the couch to pull them on. Sans glances at you from where he's slouched to watch the tussle, and he tilts his head as he notices the boots. "hey, kiddo. going somewhere?"

"Science experiment," you answer, struggling with your second boot. "Who won the dish fight?"

"dunno."He scratches his head nonchalantly. "it might have gotten abandoned when i sorta suggested that a true friend would do the dishes. then those two got into a fight about who was the better friend, and wouldn't let the other into the kitchen."

You straighten from your quarrel with your boots and stuff your arms into your coat, pulling your mittens on as you go. But when you turn to make a break for the door, Sans is blocking your path, holding the scarf Undyne made for your birthday in his hands. "whoa, slow down there, buddy. if we let you catch a chill, tori's going to give us the cold shoulder."

You snicker at the joke, dancing from foot to foot as your mittened hands fumble for your zipper. Sans bats your hands away and zips you up securely before he tugs the furry hood over your hair.

"Okay, I'm good!" You dart past him, but you don't get far before the birthday scarf lassoes you and drags you back. "Aw, come on, Sans!"

"welp. someone's squirrely today." Sans starts wrapping the incredibly long scarf around your head. He's got a while to go, since it about twice as long as Undyne is tall.

"You mean 'cause I'm a little nuts?" you ask innocently.

Sans gives a quiet snort of amusement and pats you proudly on the head. "heh. good one, kid." Giving the scarf a ninth and final wrap, he knots it securely at your throat. Most of your face is covered and just your eyes are peeking out over the pink and blue yarn, but at least you're nice and warm.

"Are you done yet?" Artie calls impatiently from the door. "Science is waiting!"

Sans shoves his hands back in his pockets and gives you a curious look. "what kind of science are you doing, anyway?"

"Gravity," you answer with a grin, and wink at him before you run for the door.

"UNDYNE, STOP BITING ME, YOU ARE GOING TO BREAK YOUR TEETH AGAIN AND- HEY!" Papyrus struggles to free himself from Undyne's chokehold. "WAIT! I, PAPYRUS, BABYSITTER EXTRAORDINAIRE, WAS NOT CONSULTED ABOUT THIS FIELD TRIP! FRISK, WHAT WOULD TORIEL SAY?"

"It's educational, Papyrus," you call as you pull open the door. "We're doing science!"

And you're free. Laughing, you chase after Artie, leaping down the porch steps and tumbling into the drifting snow. Artie faceplants almost instantly. They figured out how to use their arms for typing in a matter of hours, but they still haven't quite gotten the hang of catching themself when they fall. But the snow is deep and soft, and they're up again in a minute, giggling as they run ahead of you.

The street is largely empty, which works just as well for you. No cars to mess up the nice snow that fell last night. At first, when the skeletons moved into the friendly house at the end of the lane and Undyne and Alphys claimed a house at the top of the street, nobody else wanted to live there. But slowly, over the last year, human families with kids started moving into the empty houses. They're still a little wary around the monsters, but more and more of the kids have started playing with you and Artie on the weekends. They're still in human schools, though, which means you and Artie have the street to yourselves for a while.

"So what are we supposed to be investigating again?" Artie calls over their shoulder.

"If things made of different stuff falls at the same speed," you answer, skidding to a halt next to them at the entrance to the little park halfway down the street. The trees all dropped their leaves ages ago, and the low, strong limbs, perfect for climbing, seem to beckon to you. An idea hits you, and with small gasp, you plunge your hand into the snow and pull out a small, round stone from the decorative landscaping. "I know how we can test it! Quick, make a snowball that looks like this rock!"

You've been friends with Artie long enough that they already know where your idea is going, and if there's one thing Artie loves their robot arms for more than typing, it's climbing. They don't need convincing. It takes just a minute for them to pack a snowball with their feet, and they bend over and grab it in their mouth to free up their hands for the trees.

A second later, Artie cries out, their words muffled a bit by the snowball. "Ack! Brai' freeze!"

"Here, switch." You grab the snowball out of their mouth and stick the rock in its place.

"Be'hr. Tha's Friss!"

Together, you help each other scale the biggest tree until you're sitting on a broad, sturdy branch with a clean drop below you. There was a lot of discussion on your way up the tree about the best way to conduct your experiment, and you're both watching the snowball and the rock intently as you line up your hands, making sure both projectiles are at exactly the same level.

"Okay, ready?" You inch closer, pressing your arm against Artie's so their sensors can feel exactly when you let go. "Three… two… one… NOW!"

Holding your breath, you watch the experiment unfold, your snowball and rock dropping together and picking up speed as they plummet toward the ground - just as Undyne wanders past, clearly looking for you.

"Hey, punk, where are you-"

"-Undyne, no, LOOK OUT!"

Your warning piles on top of her words, but it's too late. The echo of the rock cracking against her head echoes throughout the little park. You and Artie stare down in horrified silence at her as she stands motionless until, very slowly, she tilts her head back.

"Did you," she begins, deep and ominous. "Just drop. A ROCK on me?"

Artie buries their head against your shoulder, and you bite your lip, unsure of what to say. Slowly, you tug the scarf away from your mouth. "I'm so sorry, Undyne."

"You should be," she growls, and picks up the rock. "This… this… is INEXCUSABLE!" With a flex of her hand, the rock crumbles to dust. "WHERE IS THE PASSION? WHERE IS THE ENERGY? THAT IS NOT HOW YOU HIT SOMEONE WITH A PROJECTILE, FRISK!"

She stoops, gathering an armful of snow, and crushes it into a snowball as big as Artie. "This is how you hit someone with a projectile! NGAAAH!"

You and Artie are both screaming, and you cling to each other for dear life as the snowboulder hurtles toward you. It smacks into you a second later, hurling you from the branch in a shower of ice and snow. You scream all the way down until you hit the snow, and the fluffy white drift swallows you whole.

"UNDYNE, HAVE YOU SEEN… WAIT. WAS THAT MY HUMAN?"

"Don't worry, Papyrus, I've got this covered. I'm helping them science. I'm a teacher, yanno."

"YOU'RE A GYM TEACHER!"

"AND YOU'RE AN ASSISTANT GYM TEACHER! SO ASSIST ME!"

You struggle from the snowdrift, coughing and sputtering, and grabArtie's ankle to pull them up after you. Once both of you are mostly free of the snow, you look at each other, and collapse against each other in a fit of giggles.

"So which one of us hit the ground first?" you ask Undyne through your laughter.

Undyne rolls her eyes at you. "Pssh. Like I was paying attention to that."

"Well, we'll just have to do it again." You smile as Papyrus tugs you the rest of the way free of the drift, and you throw your arms around him, clinging tightly so that you can kiss his cheekbone.

He blushes a little, giving a quiet "NYEH-HEH," and brushes the snow from your jacket before looking hopefully at Undyne. "DO YOU THINK THAT'S ENOUGH SCIENCE? HOW ABOUT SOME NICE HOME ECONOMICS INSTEAD?"

"Uhhh, I don't think so." Undyne folds her arms. "The whole point of Science is proving things are repeatable, right? So they have to repeat the experiment until they get a statistically significant conclusion." A second later, she realizes you're all staring at her, and her brows draw together. "What? I DO LISTEN TO ALPHYS, YOU KNOW!"

"oh, here's where you went." Sans ambles up behind Undyne, his hands in his pockets. "what'd i miss?"

"Science!" Undyne strikes a pose.

Artie finally manages to clear all of the snow out of their eyes, and blinks up at Undyne. "Yo, Teach, aren't you cold?"

With a glance down at her bare arms, Undyne scoffs. "Come on, I'm too tough for cold. Snow takes one look at me and melts in terror."

"I can attest to that!" calls the little snowman at the far end of the park, and you wave at it from your perch on Papyrus' hip.

Undyne just grins. "See?" Whirling, her hands on her hips, she looks at you in much the same way that the Dogs look at a stick, and you cling a little more tightly to Papyrus. "Now, seems to me the problem is you're not in the experiment enough. What is it that Toriel's always yammering on about during staff meetings?"

"PROMPT MARKING?"

"No."

"NOT SLIMING THE CHILDREN?"

"NO! Come ON, Papyrus!"

"yeah, bro, throw her a bone."

"EXPERIENTIAL LEARNING?" Papyrus offers, glaring at Sans.

"Yeah, that thing!" Undyne crows. "You gotta EXPERIENCE the experiment, punk! Here, check this out."

She reaches forward and plucks you out of Papyrus' arms. Before anyone has a chance to realize what she's planning, she's already hauled her arm back. You can feel her muscles coiling like steel beneath you, and in another instant, you're airborne, hurtling toward the clouds. Over the fading shouts of the skeletons beneath you, you can just make out Undyne's words.

"WHAT? KIDS BOUNCE, RIGHT?"

Fundamental rule of gravity. What goes up, must come down. The thought is reassuring as you hurtle onward toward the sky. You draw a deep breath as you begin to slow, arcing gently over the park. It's so quiet up here, and the air is crisp and cold. Spreading your arms, you take a moment to look down at the trees below you, and the houses curling around the lane. From up here, you can just make out the big house on the hill in the distance. It's funny - that house may be where you live most of the time, but it never feels weird to stay with Sans and Papyrus, or Dad, or even Alphys and Undyne. You don't have a bedroom at Alphys and Undyne's though - any time you stay over, they declare it a slumber party and you camp out in the living room in sleeping bags, so there was never much of a point.

You have a big house on the hill, and it's home. But you have a bunch of little homes too, and each one has its own thing that makes it special. From here, you can see them all.

It fills you with determination.

For one brief, glorious moment, you hang in the air, neither rising nor falling. Weightless. Your laugh rings out, bouncing off the clouds above you. Then, you're moving down again, falling faster and faster as you barrel toward the trees. As you near the tops of the branches, you tuck your knees against your chest, and you can make out the voices below you again.

"-AAAAH! CURSED TREES! WHERE IS-"

"-left, bro. left!"

"-way you guys are carrying on you'd think they were made out of GLASS or something-"

The air around you erupts in a spray of snow and ice, and it glitters like diamonds in the sun. Slowly, the shimmering falls, and as the air clears, you find yourself caught between two pairs of bony arms. A great, long skid leads across the park toward the snowdrift that half-buries you. After a long, frozen moment, the skeletons begin to pull themselves free, shaking off the ice, and you find yourself the focus of two surprisingly intense gazes for a pair of brothers who don't have eyes. Unable to help yourself, you laugh and clap your hands. "Let's do it again!"

With twin sighs of relief, Sans and Papyrus sag toward each other, trapping you snugly between them.

"i don't think so, kiddo. that's enough science for one day. how 'bout a nice nap instead?"

"FOR ONCE, I AGREE WITH SANS."

"Yo, Frisk!" Artie bounds over the drifts toward you, trailing Undyne in their wake. "That was AMAZING!" Dancing in place, they look entreatingly up at Undyne. "Can I try?"

"Sure, runt, why not?" Undyne grabs Artie's head, lifting them off the ground.

"Sweet!" Artie raises a robotic hand to punch the release button on their chest straps. With a soft whir, the arms go limp and fall to the ground. "Fire away, Teach!"

"PERHAPS YOU OUGHT TO RECONSIDER," Papyrus interjects uneasily. "WHILE THROWING CHILDREN IS UNQUESTIONABLY AMUSING, THE AMOUNT OF AMUSEMENT WE WILL HAVE IF THE QUEEN FINDS OUT IS, I SUSPECT, NOT VERY MUCH. AT ALL. CONSIDERING THAT WE WILL BE DEAD."

"Or on fire," Artie points out helpfully. "Remember when those angry humans came to the school waving signs and she set them on fire? That was so awesome!"

You glance up as a shadow falls over you, and a huge smile crosses your face. "Hi, Mom!"

Papyrus lets out a little screech, and there's some amount of jostling as the skeletons both try to make sure that you're between them and Toriel. She's giving her Headmistress Look, but there's no fire. Yet. Both of her hands are holding tightly to the handle of the large picnic basket she's carrying.

"Am I interrupting something?" she asks sweetly.

"Yo, Mrs. Dreemurr! We're doing science!" Artie calls.

Toriel raises a brow. "So I see."

Without a word, Undyne slowly puts Artie back down in the snow and lets go of their head.

Your mother continues as though she hadn't noticed. "Artemisia, I have been meaning to speak with you about your Science homework lately. Have you been getting help from a grown-up?"

Artie looks down, scuffing the snow with a toe. "Yes, ma'am. From Alphys."

"Oh, good!" Beaming, Toriel pats Artie on the head. "You have been working so hard on sharing and cooperating, I was concerned that you weren't paying enough attention to asking for help. Well done."

You grin even harder as Artie's face brightens with pride. One of the things the humans whose kids are at the school still don't quite get is the importance that monsters place on asking for help and supporting each other when you get into trouble, so it's a pretty big part of the report card.

Shifting the basket to one hand, Toriel picks up Artie's arms, shaking the snow off before holding them out. "Now I think you had best run along home. It is nearly time for dinner."

Artie backs into their arms and locks them into place before turning to wave at you. "Later, Frisk. Good homeworking today, dude!"

From your little nest of skeleton arms, you wave back. Toriel watches until she's satisfied that Artie is safely on their way home, and then turns back to you and your science assistants.

"Undyne?"

"Yes ma'am?"

"Go home."

"Yes ma'am!" As meek as she ever gets - which is still not very - Undyne gives you a friendly punch in the arm and flashes you a grin full of sharp teeth. "Later, punk! Training bright and early tomorrow! We're going to practice throwing rocks!"

You groan, but Toriel isn't done yet. As Undyne leaps the fence around the park and runs down the street, Toriel gives the three of you The Look, and the brothers inch even further behind you. "Now then. Shall we get my child out of the snow?"

You know it's serious. There aren't even any puns as Sans and Papyrus mutter apologies and free themselves from the snowbank. With a skeleton holding either hand, you follow Toriel back to the house in silence until you can't take it any more. You let your steps slow until the brothers are practically dragging you, waiting until they turn their heads to see what's wrong. As soon as they do, you rush forward, and you've done this so many times that they don't even need to think about what comes next. You let out a squeak, trying to hold in your laughter as your feet leave the ground, and your scarf slips down as you swing between the brothers until it can't hide your smile any more. By that time, Mom is smiling too, and she shakes her head with a sigh. But the scary mood stays broken, and your trip back home is measured in swings and laughter.

"NOT THAT IT ISN'T A DELIGHT TO SEE YOU, YOUR QUEENLINESS," Papyrus says as they struggle together to free you from your winter clothing. "BUT WE WEREN'T EXPECTING YOU HERE SO SOON. HAS YOUR TRIP BEEN CANCELLED?"

"Sadly, no - oh,look, there is my little popsicle!" Toriel bumps her nose against yours as she gets the last loop of your scarf off. "But we had a little time before the car arrives, and I thought that a pie would be nice for you to have with dinner tonight."

Now that the scarf isn't covering your nose, the smells of apples and cinnamon curl around you like a warm, fuzzy blanket. You wiggle happily as Sans tugs your coat over your head, not bothering to undo the zipper.

"OH." Papyrus picks up the basket and peers dubiously inside. "UM. THIS IS A VERY THOUGHTFUL SWEET QUICHE WITH NO EGGS, YOUR MAJESTY."

"hey. hey tori. what did the apple say to the orange?"

"I find you very a-peel-ing!"

Sans and Toriel break into gales of laughter so strong they can barely manage getting you out of your boots. With a strangled sound, Papyrus rises to his feet and storms toward the kitchen. "YOU REALLY, REALLY SHOULDN'T HAVE."

Wiping a tear from her eye, Toriel reins in her laughter and kneels in front of you, resting her hands against your shoulders. "Just between us," she whispers, "I also wanted to hug you again before I go."

The reminder stings a little, and the smile slips from your face. Frowning, Toriel cups your cheek in her hand, her fur soft against your chilled skin. "Oh, my child, no need for that. I will be back before you know it."

Your breath leaves you in a rush as memory slams into you, unbidden. Warm brown eyes framed by dark hair. A familiar, distantly beloved face smiling at you. A gentle touch against your hair. "Oh, Katie, don't cry. We'll be back before you know it."

"Frisk? My child, what-?"

You throw yourself at your mother, wrapping your arms around her neck and clinging for dear life. Her arms are around you at once, wreathing you in the scent of cinnamon and spices, her warmth sinking deep through your sweater to fight the chill that settled into your heart. You feel her move, and look up to see her exchange an understanding look with Sans. Sighing, she pulls you into her lap and strokes your hair as she rocks you.

"Frisk, did I not promise you that I will care for you for as long as you have need of me? I will be back, sweet child. Have no fear. You will have a lovely time with these nice boys for a few days, and then I will be back."

"Dad too?" you murmur quietly against her shoulder.

"Yes. Asgore as well." She nuzzles your hair gently. "Would you like to stay with him for a while when we return?"

You nod, your hands clinging fast to her pretty purple blouse. You don't want to let go.

Behind you comes Papyrus' best attempt at a whisper. "SANS, WHAT HAS HAPPENED TO FRISK? AND HOW DO WE FIX IT?"

"shhh. just let tori do the mom thing for a minute."

"BUT I WANT TO HELP TOO! ISN'T AN AWESOME COOL FRIEND ENOUGH TO CHEER UP A TINY HUMAN?"

"you're the coolest, bro, but tori's already got some mom-entum."

There's a pause, followed by a strangled squeak as Papyrus swallows his retort, and you can't help yourself. Even though you're upset, a giggle works it's way free, and Toriel's soft laughter just encourages yours. The laughter chases away your fear, and after one last, long hug for good measure, you let go and take a step back.

"There, now. That is better." Toriel rises to her feet, brushing the creases from her skirt. "No more tears, my child, or you shall make me cry, too."

"don't worry, tori. we'll take good care of the kid."

"I know you will. And Frisk?" Toriel winks at you. "I am trusting you to keep these two out of trouble. Can you do that for me?"

You nod, wrapping one of your arms around Papyrus's knee. The weight of his hand settles on your head, and you're almost reassured. Almost. You reach out with the other hand, wiggling your fingers until Sans takes hold of it. Toriel gives you a proud smile.

"Be good, my child. I will see you soon."

She sends the first text not two minutes after the door closes behind her. As Papyrus heads to the kitchen to start wrestling your dinner into submission, you plonk yourself down on the floor to read your phone. Sans plops down behind you a moment later, and you lean back against him as you read, his arms around your waist and his chin in his favourite spot on top of your head.

To the familiar sounds of Papyrus yelling challenges at the tomatoes, you scroll through the incoming texts. Sans snickers quietly as he reads over your shoulder, and you breathe a long, comforted sigh.


Dear Frisk,

Hello! I hope you are staying out of trouble. The car that is to take us to the airplane is very large. They say I should not use my phone when we are on the airplane, but I will send you a picture when we land.

Be good!

Love,

Mom ] : )


PS. I put some clean underwear in the picnic basket under the pie. Just in case. You can never have enough clean underwear. In case of accidents.

Love,

Mom ] : )


PPS. Do not have accidents. Stay in one piece.

Love,

Mom ] : )


PPPS. Asgore is here too. He says to say hello.

HELLO!

Asgore, do not use all capitals. Alphys says that means you are shouting. It is very rude. Unless you are Papyrus; that is just his way.

OH. SORRY! HOW'S THIS?

Asgore, no.

HOW DO YOU TURN THIS OFSNGTHSGFSN

Dear Frisk,

Here is a picture of a small dog.

Love,

Mom ] : )

[attached is a photo of an extreme close up of a wet brown nose]


"HEY!" Papyrus calls from the kitchen. "THIS EGGLESS QUICHE COMES WITH SUPERHERO PANTS! THAT ALMOST MAKES UP FOR THE LACK OF EGG!"

"oh, would you lookit that, you change colour. red's a good look for you, kiddo."

Giving a quiet, dismayed squeak, you bury your burning face against Sans' shoulder. He laughs, but there's no malice in it, and he reaches back to snag a blanket from the couch and wrap it around you both. Safely cocooned in the blanket and in Sans' hug, you let yourself get lost in the soft, sweet comfort of the feeling of home.