Frisk's small shoes crunched against the thin layer of snow that had accumulated outside. School had just gotten out, and just like every day after school, Frisk had to hurry home to Sans and Papyrus since Toriel didn't come home until past four. Being the school's best teacher, Toriel had more than a few things to do before leaving.
Upon entering their home that was nearly identical to Papyrus' house but with two more bedrooms, Frisk smiled as everything was just the way they preferred it; Sans was asleep on the couch, Papyrus was in the kitchen with Undyne, and Alphys was watching an Anime marathon of some sort that involved swimming. Only Papyrus and Sans lived with Frisk and Toriel- Undyne and Alphys lived together next door but visited almost every day.
"Ah, Frisk returns at last!" Papyrus rushed out of the kitchen and held a large blue plate of... something that resembled a waffle but not nearly cooked enough to be a waffle in front of Frisk. It smelled like a waffle mixed with salt and soap and the grey-ish mush appeared to be... smiling..? "I've been branching out from my incredible spaghetti-making skills to bring you something new- a waffle... made entirely out of spaghetti noodles in the shape of my face! Is it not incredible?! It has all the major food groups; spaghetti, breakfast, and, um, handsomeness!"
Frisk smiled, trying not to show any form of disgust on their face. It wasn't the 'food' that was making them feel sick. In fact, Papyrus had made much, much worse in the past year, but Frisk felt dizzy, hot, and nauseous all at once. The room spun and swayed in a manner that resembled a ship in a violent storm. Not even Papyrus' cooking could manage those symptoms. Soon, Frisk went from smiling to falling in a matter of seconds.
Somehow, Sans was able to shoot up from his spot on the couch to catch them faster than Papyrus could fling his concoction to the side to catch them himself.
Frisk wasn't conscious long enough to really react to the situation themself, so instead of Frisk falling with an expression of pain or fear, they held a straight face. The faces that surrounded the child soon faded into a soft blur, as did everything else in the room. The last thing Frisk heard before falling out was Undyne telling them to stay strong.
A little over an hour had passed since Frisk became ill. They were tucked into small, tidy, blue bed as Toriel, Papyrus, and Sans quietly watched over them while Undyne and Alphys went out to get some medicine, or as Undyne called it, "Illness-killing Weakling Syrup."
As Frisk came to, there was a collective sigh of relief. Toriel felt their forehead earlier and identified it as a fever; not a serious one, but it was the first time that Frisk was out in the cold on the surface since they had fallen into the Ruins and made it to the rest of the underground. It was only normal for their immune system to be a bit off, what with all the temperature changes.
Being the natural mother that she was, Toriel couldn't keep herself from lovingly patting Frisk on the head in an attempt to comfort not only Frisk, but also herself. "I am so, so sorry that this happened to you, my child," Toriel said in a sad yet somewhat hopeful voice. "It will be all right. Alphys and Undyne will be back with your medicine, and Sans and Papyrus are here to take care of you. I have some homework to grade right now, so I'll be back later. Sleep well." She gave Frisk and kiss on the head and left the room.
Papyrus, who was sitting cross-legged on the floor, leaned over to Frisk and whispered, "Psst, Frisk. I want to experience as much of the surface as possible, remember? This includes the experiences that make others 'sick'. I have never been sick before, other than when Undyne talks about her weird vomit puzzles. Do me a favor and describe what you're feeling right now."
"I don't think you'll ever be able to really understand how Frisk feels right now," Sans said.
Papyrus turned to Sans with a stern expression. "What?! Why not?"
"Because you aren't human."
"So?"
"I'm just saying that nobody like you could understand. Heh."
Sans and Papyrus argued a bit before Sans got bored and fell asleep. "You lazybones. We're supposed to look after Frisk!" He sighed and looked at the small child, who had started to wake up just a little. "Well, I guess this is just another job for the great Papyrus! Nyeh heh heh!"
It wasn't long before Undyne exploded into the room with a literal mountain of different brands and varieties of medicine in her arms that piled up way over her head. Alphys quietly reminded her that Frisk wasn't feeling well, so she toned down a little... just a little.
"So, what kind of sissy liquid does Frisk need?" Undyne asked Papyrus, who told her that they needed something for a fever. Undyne dropped the medicine into a heap in the middle of the room and Alphys looked through them.
"W-we bought extra, um... everything j-just to be sure," Alphys stated while rummaging through the pile, tossing a few boxes aside. "Here we go, children's fever medicine. It's supposed to t-taste like cherries." Alphys gently nudged Frisk awake and held the cap full of red liquid in front of them once they sat up.
Frisk rubbed their eyes sleepily and looked up at Alphys.
"Say 'Ah!' Frisk. This'll help you get better."
Hesitantly, Frisk took a sip of the liquid and immediately regretted it. It was incredibly bitter and had a hint of artificial sweetness to it, which made their face scrunch up.
Alphys looked disappointed. "C'mon, Frisk. You g-gotta drink it all-"
Out of the blue, Undyne interrupted Alphys and dramatically pushed her to the side, snatching the cap in the process. "Ngahhh! Frisk! You got through Toriel, me, and Asgore himself! Are you REALLY going to let some syrup's taste get in the way of your good health?! C'mon! Where's your determination? Just get it over with, you weenie! Do it or else I'll throw Papyrus through the window!"
"No! Please, Frisk! Do it for your cool friend!" Papyrus responded while quickly moving out of arms-reach of Undyne.
After hearing Undyne's encouraging words, Frisk was filled with determination. They took the cap and downed the liquid quickly, trying to swallow it faster than they could taste it. With a smile, they handed it back to Undyne and tried getting out of bed.
Papyrus held Frisk's hand to give them stability and couldn't stop grinning. He always felt most happy when he was helping humans out, especially if said human was named Frisk and thought of him as their cool friend.
Alphys physically looked relieved after seeing Frisk stand, while Undyne looked the same as she did before but felt a weight lift from her back as Frisk and Papyrus left the room together to go see Toriel. She was sitting at her desk in the living room in a large chair, grading papers and setting said papers next to Sans' pet rock.
"Toriel, look! Frisk isn't partially dead anymore!"
Toriel turned around and a huge smile spread across her face. She stood up and walked over to Frisk, taking their hand away from Papyrus and picking them up to cradle them in her arms. She motioned Papyrus to leave them alone and sat on the couch. "Frisk... my child... I was so worried when I heard that you were sick. I could not let my fear show in front of you, so I am sorry that I had to leave you alone. I knew that the others could take care of you and I wanted to be there too, but... I could not see another ill child. I did not want to remember you that way. I was so afraid that you were not going to make it and I could not go through that sort of heartache again. Not another child. Not my child." Toriel waited for some sort of response from Frisk, but she soon realised that they had fallen asleep. Toriel wondered how much they had heard. She felt their forehead, and to her relief, the fever had subsided. Toriel then carried Frisk back to bed and told the others that they would be better very soon.
Later that evening, in celebration of Frisk's good health, Toriel baked a cinnamon pie for everyone. Sans barely touched his, despite being so anxious for his slice. Papyrus asked for the recipe, hoping to one day be able to bake such a large and delicious pie. Undyne ate hers in a fairly barbaric manner, rarely even using her fork. Alphys was the only one who ate her slice like a normal individual. For dinner, Frisk had some leftover casserole from the other day. They weren't really in the mood for pie as a snack, so Toriel let them skip right into dinner. What with being sick and all, it was understandable that they weren't very hungry, either.
Once everybody was done eating, Alphys and Undyne went home to watch a new Anime together. Alphys described it as a dog demon that was one a quest to become a full demon while also searching for his father's sword. Sans fell asleep on the couch again- this was a habit that he was trying to break out of, but ever since he had a couch that didn't hurt you when you sat on it, it was almost unpreventable. Papyrus was on the computer that was in his room. He had become quite the popular gamer online with a couple thousand followers that were into his Let's Play series'.
Other than Frisk being sick, it was just your average day that ended the same as any other; Toriel told Frisk a bedtime story to help them sleep and Sans would do the same for his brother.
Frisk couldn't ask for a better family.