Author's Note: For headcanon purposes, the time gap between Chara's fall into the underground and Frisk's fall was hundreds of years. That was a little snippet of info that was never explicitly stated, but is important nonetheless.

Sans lowered himself onto a lawn chair beneath the old maple and groaned at a hard day's work. It wasn't quite noon yet, but it felt like a full day to him. He'd woken up early and made the kids breakfast, so he decided he was entitled to his customary mid-morning nap.

He settled his skull against the scuffed wicker and did a slow survey of the neighborhood.

It was quiet, like always. The suburbs of Frisk's hometown were nothing if not sleepy. Rows of blocky, same-ish houses lined the streets and hid in the shade of enormous elm trees.

'Idyllic' was a word that often came to Sans at times like these. He hesitated to say it aloud—fearing he'd jinx everything and call down some catastrophe—but the word still lingered in the back of his head.

A jogger or dog-walker would occasionally appear on the sidewalk and offer Sans a nervous wave. Sans always donned a disarming smile and tried to be as non-threatening as possible. Making a good first impression was important. Especially considering how skittish most humans seemed to be.

They were nothing like Frisk had first been, so fearless, so heedless of his own safety.

Sans wasn't quite sure why that was. Frisk never talked about his past, even after returning to the surface.

Sans didn't like to pry. The kid seemed happy enough with how things had turned out. No need to go digging.

A breeze picked up, eliciting a song from the porch's wind chimes and setting the old maple's branches in motion. They swayed gently and stamped Sans' hoodie with a shifting patchwork of light.

Sans squinted through the leaves at the sun and grinned. Even after months on the surface, it never ceased to fascinate him. He was drawn to the way that it crawled across the sky, constantly shifting from dawn, to day, to dusk.

It felt good to track time with something other than a ticking clock.

oh, right.

He rooted through his pockets and fished out a round, metal object. He held it up at arm's length and let the light refract off its polished surface.

It was a watch made of thin metal plates, precisely riveted to give it a smooth edge. A jumble of churning, copper gears spun in the center and kept a trio of hands in motion. A small four-digit bar, like an odometer, sat at the bottom. 0000.

like it should be.

Sans' first priority upon reaching the surface had been to reset the original watch. But the task had been borderline impossible. The routine that tallied the loops was hard-wired into the programming. It couldn't be reset to zero.

Although Sans had kept telling himself that everything was fine, that he didn't even need a watch anymore, glimpsing that 9999 made his vertebrae itch. How could he know the world was still in motion without some way to be sure?

He had spent weeks on the watch, toiling alone in the rotten gardening shed he'd converted into a workshop. Pap, Tori, Asgore, Frisk, and the others had come to inquire about him, but they'd all gotten the same cold shoulder.

Eventually, Asriel had stopped by—looking a lot less lost than usual. He had offered Sans a red-eyed stare, and a fresh piece of pie from Toriel.

"Having trouble? This is for you, by the way. Mom says you can have another if you come outside to get it yourself."

"thanks kid. one's plenty."

"So, listen, Sans. This is, uh, Chara speaking, okay?"

Sans had chuckled through his teeth. "you know, the eyes kinda give it away. monsters aren't color-blind, you know. except maybe dog-monsters… not sure about that one."

Asriel had seemed taken aback for a moment, but he collected himself. "Well, then that makes things easier. I know what you're doing. I spent a long time on the exact same thing. For, um… worse reasons. But I thought I'd save you the trouble. That watch can't be reset. Gaster did it on purpose. I spent over a decade on that thing, and I couldn't crack it, so…"

Sans had rubbed at the base of his skull and sighed. "so, did ya bring any good news to soften the bad? Or is the pie my only consolation?"

"Wait." Asriel had cocked his head. "Have you not found the schematics yet? He buried them in the watch's code. He did that with all his inventions… How did you not know that?"

"you've got a mean sense of humor, kiddo."

"No really, look." Asriel had trotted over to Sans' portable lab terminal and combed through the entirety of the watch's code in a matter of minutes. "See. Right here… It's really not that hard to catch…"

"you can be a little creepy sometimes, did you know that, kid?"

Asriel had laughed a little too long at that. "I'm three hundred years old, Sans."

Sans shook his head to disperse the memory and shifted on the lawn chair. He drew the watch in close and flipped it over. The back plate was covered in a series of scratches, shallow and precise like an artisan's cut. They linked together to form three brief words: just in case.

Sans ran his thumb over them and mused.

Asriel—or Chara, to be more specific—had carved them with a pocket knife right after they'd finished making the watch.

Sans didn't like to admit to himself—and certainly hadn't done it out loud—but he couldn't have made the new watch without Chara's help.

Despite all his fears, things had worked out—seemingly without him raising a finger. It had been months now, and nothing had gone wrong. Monsters were acclimating to the surface, tensions were low. Some monsters had even received free housing as a sign of good faith from the humans.

A paralytic twinge of shame still affected Sans from time to time. All his paranoia had only managed to injure an innocent kid and jeopardize this whole happy future.

good thing there was someone more stubborn then me…

Sans returned the watch to his pocket and stretched. A two hour nap seemed fair. It was Saturday, after all. The kids would do nothing but watch cartoons all day.

He closed his eyes and imagined he could feel the warmth of the sun on his bones.

Two hours quickly turned to five, and Sans woke in shadow. The sun had already begun its descent and was hiding behind the house's chimney.

Sans rolled his shoulders and considered the merits of an early bedtime. Pap was out for the day, so he wouldn't be heckled about it.

He shrugged and drew out the watch. Depending on what time it was…

7699.

Sans' jaw went slack. He turned the watch left and right, making sure it was real.

7699.

Sans rocketed to his feet and roared incoherently. A surge of his magic tore branches off the elm tree and sent the lawn chair cartwheeling through the air.

He stormed across the grass and towards the shed, clenching the watch in both hands as if he were trying to choke it to death. He kept glancing about, expecting rends in space-time to open up in the street or on the side of his house.

no. no. no! NO!

Sans kicked the shed's door open, snapping one of the hinges. He stepped inside and the excess momentum sent the door swinging drunkenly to a close behind him.

His magic eye was so bright he felt like a blue flashlight was strapped to the side of his head.

Sans slammed the watch into the terminal's port and stabbed at the keyboard with his fingers. Whatever this was, a glitch, a coding mistake, or something far worse, Sans would fix it. By any means necessary.

Black monospace text on a white background popped up on the monitor.

Sans steadied himself by gripping the wooden workbench.

Total temporal anomalies: 0

Total timeline redundancies: 0

Sans leaned in closer and squinted. "what?"

Snickers and snorts filtered through the planks of the shed.

Sans retrieved the watch and opened the door. The second hinge gave way and the door hit the floor with a clap.

Two children, one human one monster, crouched behind a bush outside and quaked with suppressed laughter. The human had a brown mop of hair, and wore jean shorts and a striped T-shirt. His entire face was beet-red and he held both hands over his mouth. The monster was in much the same condition. Despite his thick, white fur, a flush of scarlet spread across his cheeks and down to his throat. The red soul that floated over his T-shirt seemed to pulse in unison with his snickers.

"frisk… asriel…" Sans looked down at the watch. A calm inspection finally revealed the truth.

"you did not just do that..."

Sans peeled an expertly placed sticker off the watch's loop counter to reveal the 0000 beneath. He crumpled the prank between thumb and forefinger and flicked it to the ground.

"…you're getting dunked on."

The children's laughs died in their throats.

Sans could see the blue light of his own eye reflecting off their faces.

Frisk's voice was tiny and fast. "It was a joke, Sans. You know, haha. Asriel said you'd think it was funny."

Asriel wheeled on Frisk. "I didn't say that! It was Chara's idea!"

Asriel blinked. Red pooled into his eyes and they began to dart about, as if gauging escape routes. "Well, you know, uh, it was actually… SCATTER!"

The children shot off in opposite directions like jackrabbits.

"you kids are so getting DUNKED ON!"

The End

Author's Note: Yay! Finally done. I hope you guys had fun reading this, because it was certainly a blast writing it. Above everything else, I'd love to receive a comment from you if you felt compelled to read all the way to the end. I get these comments through email, and even though the story may be over, I'd still love to hear some feedback on it. Did you like it? Hate it? Do you have some insight into my writing style? You know, anything you feel like sharing.

Thanks for soldiering on to the very end. See you in the post-epilogue ;)