The grove was silent save for the sound of small fingers scraping against the dirt and grass. It didn't take very long for Papyrus to untangle the knot that abandonment had made of his mind -it wouldn't have been the first knot he'd ever untied -and with endless possibilities going through his head, only one logical course of action presented itself…

He'd have to go deeper into the serpent's den.

A door locking only from the outside sounded ridiculous since anyone could be locked inside. There was always an opening mechanism inside, so maybe giant snake skulls were no different.

Steeling his resolve, he marched right up to the door he had opened earlier, finally daring to look inside. What he stepped into was what looked like a foyer almost more grand than that of King Asgore himself -not that he'd ever been to visit Asgore -with twin grand helical staircases leading up to the second floor, at the forefront of his vision. It was quite impressive, he had to admit. The walls and fixtures were made of dark wood similar to the wood in the previous room, but much more healthy-looking, and in stark contrast to all that darkness, was the floor, made of white reflective marble; it looked so clean that he probably could have eaten off of it if he wanted to. Thankfully, his common sense managed to persevere throughout the five seconds in which this thought was crossing his mind.

His boots echoed against the walls as he took a few steps forward, and no sooner had he taken those steps than the doors slammed shut behind him. He turned his head to look at the door with dread. He wanted to run towards it and slam his fists against it, demanding its immediate reopening.

NO TURNING BACK, PAPYRUS. YOU CAN DO IT.

Keeping his back facing the door, he resumed his solitary walk. Around him, lining the walls on the ground floor, were several doors, four on each side. Each of them had different symbols engraved on them, but they were all too far to make out in the dim lighting. He had no way of knowing what they represented yet, but perhaps he'd find something if he looked around for a bit.

ANOTHER PUZZLE?

He began approaching one of the doors, the first one on his right, and yelped in surprise when he found himself stepping over something small and hard. He kneeled down to pick it up. It was a small metallic figurine, blue in color and flat; the image carved into it was a snake coiled around a rod. He decided to pocket the figure and move on.

The door refused to open when he turned the knob, and upon further examination, he noticed that the symbol he saw earlier was carved into an oddly shaped depression in the door, the inside of which was painted a bright neon green that seemed to glow eerily. He extracted the blue figurine and attempted to place it against the opening. As he had expected, it didn't fit, but he was certain there had to be more of these figures scattered around the grand hall. The hard part of this puzzle, however, was actually finding them. Fortunately, the floor was white; unfortunately, it was also vast.

After a good half hour of searching, he had managed to find what he assumed to be all eight of the door keys in various corners of the upper and lower levels of the foyer; a couple under the staircase and a couple behind the tall pillars holding the second floor of the mansion up, a few hiding between the railings. Each of the figurines was shaped like a different type of snake, and each of them was in a different color: sea blue, green, violet, red, orange, yellow, indigo and fuchsia. They were also smooth to the touch and glossy in the dull light.

Papyrus approached the first door on the right with the pink snake and fidgeted with the figure until it fit. It wasn't necessarily hard to put it in, but his lack of height made it difficult to see where he was pressing the key. Eventually, it sunk into the hole, fitting perfectly, and he heard a muffled click. With that, the door swung open slowly, revealing a small and narrow chamber with barely enough room for him to extend his short arms fully at his side. He braced himself and stepped inside.

The room was much brighter than the foyer. It was as though the very walls were illuminated. At the far end of the room, there was a large pink luminous cube with a luxurious pillow sitting on top, and on that pillow was a figurine made up entirely of small wooden cubes that seemed to resemble a serpent. Uncertain of what to do with the thing, he snatched it and placed it in his backpack.

Upon entering the other seven rooms, Papyrus found similar objects in different shapes, but all made up entirely of cubes. He gathered them all; obviously they must have been important or there would have been no point in opening those doors.

After he had all the wooden figures, he went up the stairs to look for the next door he needed to open. While the second floor seemed large enough that it would have more than one door, there was only one. It was right between the two staircases and was larger than any door Papyrus had ever seen in his entire life. There was a depression in the door shaped like a perfect square, so proportionately small and nondescript that he almost missed it. In the center of that depression was a single cube, affixed solidly; it seemed to be made of the same wood of the eight figures he had collected.

He shrugged his backpack off of his shoulders and set it carefully on the ground. He then began to rummage through, pulling out all the wooden figures. His hands brushed over the plastic wrapping of the gummibones he had bought from Mr. Feely and he felt a pang of hunger slide down his spine and rattle his bones. He gave the bags a cautious look. He only had five and he wasn't certain he'd be able to eat later if he didn't save them.

Shaking his head to snap himself out of it, his attention went back to the puzzle at hand. He held a couple of the pieces together and compared them. They all seemed to be made up of exactly twenty-seven small cubes. It occurred to him that he may have had to figure out a way to make them all fit perfectly into the gap in the door, but with their irregular shapes, it looked to be a nearly impossible task.

He let out a small sigh, fiddling with one of the snake-like figures in his hand. Upon closer inspection, it seemed like the cubes rotated in place; was that the key to solving this puzzle? He could feel the gears in his head kickstart as he tweaked the small cubes. If he could get the pieces to form a larger cube, it would be easy to fill the hole in door.

It only took a couple of minutes for Papyrus to rotate the last cube and the first piece of the larger puzzle was complete. He placed the piece in one of the corners and heard a clicking noise. He tried to pull the piece back out, only to realize that it was now fixed in place.

Knowing exactly what he had to do, he began working on the other seven pieces. As he did, he thought about his predicament. He had to admit that he was somewhat enjoying these small serpent puzzles, though the fact that he was trapped made his enthusiasm lukewarm at best. He couldn't very well sit around and solve puzzles all day when Sans was probably worried sick. He needed to find a way out and as long as he couldn't go back the way he came, the only way to go was forward.

Alphys alternated between holding her breath in anxiety and letting out long, tired sighs. She could only guess at what Sans wanted from her. The two of them rarely ever spoke and the last time they were on speaking terms was when she found him lurking around her laboratory on her first day of work. He had told her that he stumbled in by accident, giving her a mysterious smile before wandering off deeper into the lab. When she had gone after him to find him, he was nowhere to be seen.

Nowadays, she never spoke to him and she had never seen him in her lab again. She still looked, once in a while, for a hidden door -anywhere Sans could have disappeared to on that strange day, but her efforts proved futile, and eventually she gave up. Now, however, he was coming to her lab to ask for her help. What could he possibly want?

"yo."

"A-Ah!" Alphys yelped, stumbling back into her rolling chair and nearly rolling out of her lab. "Sans. Y-You're here already?" He was standing casually, with his hands behind his back, nearly two feet away from her. She had scarcely put her phone down. How had he gotten here so fast?

"i was in the neighborhood," he replied smoothly, raising one hand to idly scratch his chest. "you look surprised."

Alphys let out a series of nervous chuckles. "Ah, I hadn't expected you to get here so fast."

Sans grinned. "i knew a shortcut." That's what he had told her the first time they had met in her lab before disappearing into thin air.

"C-Can I… help you with something?" she asked, trying not to look like an accident waiting to happen. "You said you needed help?"

"Papyrus is missing," he said, more seriously than she had ever heard him speak. "You're going to help me find him."

"I am?"

"You are."

She bit her lip and felt her tail suddenly grow heavy. "B-But… wouldn't the guards be more helpful? I don't see h-how…"

"i have to make sure of something," he told her. "do you know anything about the core?"

"The CORE?" she asked, unsure of what that had to do with it. Unless… Sans was worried that Papyrus had fallen in. "I didn't create the CORE," she replied uncertainly. "The Royal Scientist before me -"

"Do you know anything about it?" There he went again with that icy tone.

"A bit?"

"a bit?"

"I h-have cameras all around it and I can control its layout from my computer. If you think Papyrus is there then -" She stopped herself before finishing her sentence. "Wait! My cameras! Where did you last see P-Papyrus?"

"the hotland apartment building," he told her, raising his eyebrow… somehow.

"G-Great!" she told him, rushing to her computer with renewed energy. "I-I can l-look… I-I mean… find. I can f-find him using my cameras. All I need to d-do is r-review the footage from earlier today and I can see which way he went. Maybe h-he's not in the C-CORE after all!"

Sans looked tense, but he didn't show any signs of rejecting this idea. It would definitely be a relief if Papyrus had gone somewhere other than the CORE. He stood by as Alphys typed into her computer rapidly before bringing up the footage of the apartment building lobby from earlier. It was empty save for a snack vendor standing by the door. After a minute, Papyrus came into view, making a beeline for the vendor. Sans's eye sockets seemed to darken as he watched the man grab Papyrus's hand and walk off.

"W-Well… he's not in the CORE, I guess! S-So he's safe, right?" Alphys said, but Sans didn't speak.

He reached for the computer interface and changed the surveillance camera view. This one showed one of the paths in Hotland. When the pair reached a certain elevator, they were no longer on any of Alphys's cameras, but Sans didn't need a surveillance camera to know exactly where they were headed.

"I-I didn't know we had an elevator there," Alphys remarked, leaning into the screen. "Where did that come from?"

"WOWIE! I DID IT!" Papyrus said to nobody in particular, looking at the seven perfect cubes on the ground in front of him. Wasting no time, he grabbed them two at a time and began to tile them in the hole, around the center cube. When he was done, he stared at the door expectantly, only for his excitement to die down when nothing happened. He tugged at the large door, but his tiny bones could not make the door budge.

He sighed and scrutinized the door once more. Perhaps he had done something wrong. His eyes ran across the surfaces of the cubes and noticed that a couple of them had tiny glowing runes in the center, each perhaps, signifying the color of the room they had been found in. With a frown, he tried pulling out one of the non-glowing cubes. It fell out at his touch, almost as though propelled by a spring mechanism. He made sure to catch it before it hit the ground. Rotating the object in his hand, he searched for a similar rune to the ones he saw and found it very easily. He reinserted the cube, leaving the rune facing forward, and heard a clicking sound followed by a dull glow.

Then Papyrus's next course of action became clear to him. He set to work on adjusting the cubes' orientations. When he was finished, there were a set of nine runes on the door before him. Their colors began to change in unison from red to blue to violet -rotating between each of the nine colors until they all flashed a bright white. Before he could react, they all went dim and he heard a loud clank.

It was then that he was completely certain he had done it. The door was open and he could finally proceed to the next chamber -or maybe even leave if he was lucky. He watched the door with bated breath as it slowly, but surely, began to rise into the ceiling. He couldn't hold the sigh of relief that slipped past his clamped jawbones.

Past the door was a very bright room; it was quite refreshing compared to the previous rooms he was in, but also quite small. The tiles on the floor were bright and a random multicolored mess. The entire room was five tiles wide and six tiles long. It almost resembled a puzzle he had seen in a book once, so he was tentative about going forward. Of course, the one in the book had clear instructions for him to follow, but this room did not.

Taking in a deep breath, he stepped onto the first tile, which was colored pink. Nothing happened. He let out a nervous chuckle and adjusted the straps of his backpack. All this anxiety was making him hungry, but he wouldn't give into his hunger yet.

There were five tiles around him: one red, two yellow, one blue, and one green. The ones directly adjacent to him were green, red, and blue. He tried going directly forward to the red tile, only to find himself blocked by an invisible barrier. The blue one to his left reminded him of water and he did not wish to get his boots wet, so he elected to save that for last. All that was left was the green tile. He took another hesitant step to his right and let out the breath he was holding when nothing happened.

His next step also made him cautious. There were also five tiles around him now: the pink one he had just come from, the red one in his top left corner, the yellow one right in front of him, a blue one to his left, and finally an orange one in the top right corner. He can hear a low buzzing coming from the yellow tile, and thus decides to move to the left again. However, he doesn't bother to exercise caution as he does, so his boot sinks into the tile, and along with it, his entire leg; the rest of his body soon follows.

He was right. The blue tile was definitely water, although it was much deeper than he had anticipated, and not all of it was water. It was almost as though only the first couple of inches were water and the rest empty air. His pelvic bone soon hit a hard, wet surface and he began sliding through the darkness with no way to slow himself down.

The trip down the long slide seemed to take ages, and after the initial shock wore off, he found himself wondering who had even made such a long slide. Perhaps it was an overly excitable child, or simply a monster who was very enthusiastic about slides. Whatever the case, he could definitely say he was in the slide for a good ten minutes, maybe even longer, before he could see the light again.

The second he could see again, he was thrust into a pool of water. Thankfully, he did not have lungs and thus had no need for oxygen, or else being submerged would have been rather uncomfortable indeed. It took him a moment to gather his bearings and swim up to the top of the pool, and when he did, he finally got a good look at his new surroundings.

He was in Snowdin. Or at least, it looked like he was in Snowdin. It wasn't any part of Snowdin he'd ever seen, but it was the only place in the Underground with snow. There were trees all around him, so it was not quite clear where he was meant to go.

As he climbed out of the pool, he noticed one of the trees in the clearing had a note pinned to it. He scrambled over to it and scanned the words on the page.

THE COLORED TILE PUZZLE

Pink does nothing to you. Please do not hesitate to step on it.

Red is impassible. Please do not try to pass.

Yellow is electricity. Stepping on a yellow tile will be quite unpleasant.

Green means you will have to fight another monster. I am only too sorry for this.

Orange will make you orange scented. I'm not quite sure why we even have orange tiles.

Purple is slippery and will make you slide to the next tile. You will also be lemon scented. I don't fancy lemons very much.

Blue tiles are water. They're pretty harmless. Unless you smell like oranges. And it has been scientifically proven that piranhas enjoy the taste of oranges very much. However they don't like lemons at all. So if you smell like lemons, you should be fine.

It should be noted, that I am not a piranha. Just putting that out there.

If a blue tile is next to a yellow tile, you will be electrified.

Please have fun and stay safe.

-S

Papyrus frowned. He definitely could have used this note before he plummeted. Now it was practically useless unless he encountered another colored tile puzzle. He then caught sight of another note hastily pinned to the tree in the exact same place as the other one.

"THIS WASN'T HERE BEFORE…" he mumbled, eyeing the paper suspiciously. He picked it up and read it cautiously.

To whom it may concern,

It has come to my attention that perhaps the previous puzzle was a bit unfair. I am really sorry for this. I have prepared another puzzle for you just beyond these trees. Just go straight ahead. I do very sincerely apologize for the inconvenience. Please help yourself to the pool. The water may be a bit cold, but something tells me that won't matter to you.

-S

Papyrus felt a chill in his bones, which was odd since he was a skeleton and couldn't feel the weather. This mysterious "S", the author of these letters… who were they? S? S for who? S for Sans? Were they a friend of Mr. Feely's? And where was Mr. Feely anyway? It was strange that he hadn't come back yet. Maybe Papyrus shouldn't have gone ahead and solved those puzzles. What if Mr. Feely simply left to go get something really quickly and by going ahead, Papyrus had lost him?

He shook his head and took one last look around the clearing before leaving. The slide he had come from was actually quite frightening now that he was getting a good look at it. It was coiled around in wide arches and looked like a giant snake. The opening at the bottom was the snake's mouth, hanging wide open, with its fangs protruding menacingly from the top of its jaw.

He shuddered and turned around, going through the trees in the exact direction the note mentioned. He hoped that after all these puzzles, he would finally find Mr. Feely again and tell him to to take him home again. Maybe Sans would be on the other side of the puzzles. Sans liked practical jokes, but this was a bad joke. If Sans were actually behind this, he'd have to scold him later.

Sans and Alphys stepped out of the elevator and into a peaceful yet morose forest. There were leaves on the ground and right in front of them was what looked like the gaping jaw bones of an enormous serpent.

Alphys let out an audible gasp and faltered in her step. It was unlike anything she had ever seen. Alphys knew of animals on the surface who, rather than fade completely upon death, left skeletons in their wake. The only skeletons she knew personally, however, were Sans and Papyrus, and they were magical skeletons. She doubts either of them ever had flesh on their bones like surface animals.

"I-I-I…" she was having trouble finding the words to say, but Sans seemed to know exactly what she was thinking.

"you didn't know a place like this existed in the underground?"

Alphys had to admit. She liked Sans more when he was making puns and putting whoopie cushions on people's seats. "You already knew about this place?" Why did Sans have to get more and more mysterious every time she spoke to him? She was having enough trouble being in his presence as it was.

"unfortunately," he replied.

"W-What is it?"

Sans turned his head to face her, a faint azure glowing in one of his eye sockets. "Alphys, listen closely, because I'm only going to tell you this once." She nodded curtly, feeling like spiders were crawling up and down her body, just beneath her scales. "Go back to your lab

"W-W-What?"

"this place is a doorway to another world."

"A-Another…"

"every monster living past this point is already dead."

Alphys's heart skipped a beat. "Living and dead? But that's impossible, isn't it? O-Once you're… d-d-dead… You can't c-c-come back!"

Sans turned away from her and took a couple of steps towards the snake's skull. "not if you have determination."

"B-but there's no way for a monster to have DETERMINATION unless… you…"

"Alphys, go back to your lab."

For moment, she really, truly wanted to go back. It would have been so much easier to just cut her losses and pretend this entire day had never happened, but in spite of her apprehension, the entire notion of a place full of monsters who had come back from the dead filled her with a sense of sick curiosity. A monster with DETERMINATION? This was groundbreaking.

"No." She couldn't even believe the voice was hers, and apparently, neither could Sans, as for a moment, he dropped the serious expression in favor of a more puzzled one. He turned around to face her again.

"what?"

"I said 'N-N-No'!" she winced when her voice lost the strength it had before. "Papyrus is in t-t-trouble. Y-Y-You w-won't… I w-w-won't let you do this alone!" She tried to grin, only for it to come out awkward and halfhearted.

For a moment, Sans was silent. Then he nodded slowly, easing the tension in Alphys's chest. "welp," he started, waving one hand at her, while the other sat in his pocket. "let's get going then."

I must really apologize for being a late updater. This summer is suuuper hectic for me since I'm getting ready to move to another country :O
Anyway, this chapter may not be as eventful as the previous one, but I hope you enjoy it nonetheless.
It's a bit longer than the previous one, though, so I hope that makes up for it :D