"How?" Frisk asked, confusion and relief warring inside him. It was quite frankly liberating to know he wasn't alone in this, but the human had seen Sans die, and everything he had figured out about Flowey's power made this seem impossible. "When we met earlier, it didn't seem like you remembered." Unless the skeleton was just that good of an actor.

"It's complicated." Sans gestured to follow him further into the lab, where they reached some sort of machine covered by a large sheet. "Let's just say I scienced the shit out of it." He whipped the sheet off to reveal a large machine and began powering it on. 

"You learned how to see and avoid the resets with science?" Frisk asked incredulously. That made sense; Alphys could interact with the soul, so why shouldn't Sans be able to interact with Time? 

"Kinda." Sans sighed as the machine turned on. "Again, it's pretty complicated, but I'll give you the short version. I learned how to perceive and measure the resets some time ago. I wasn't exactly sure what they were at first, but that was what this machine was for." The screen lit up, showing multiple graphs that Frisk barely understood. 

A few keystrokes later, the graphs coalesced into something resembling a timeline. Though all the resets made the thing look almost unreadable. "I've been trying to figure out a way to counter or preserve memories through timeline shifts for years, maybe even decades at this point. Considering how often Time has been tampered with, it's impossible to tell." Sans clenched his skeletal fingers. "As you can probably guess, knowing you haven't figured it out in all that time is kinda disheartening." He smirked a little at his slight pun.

"Well, it's nice to know you're still you." Frisk chuckled, "Though I don't know if remembering makes it better or worse." He thought of the crushing loneliness that kinda power gave.

"Well, as a scientist, you can guess what I prefer." He mentioned offhandedly. "But that little conversation of ours gave me the motivation and inspiration to pull an all-nighter."

So that's where he was all day. "I'm assuming you worked something out?" 

"Right on the money, I figured out how to preserve my memories through the resets by storing them within my magic." He opened a side panel on the machine where Frisk saw complicated-looking machinery surrounding some sort of storage unit. "I repurposed the internal battery to store it so a reset couldn't revert the internals." 

That was undoubtedly ingenious, but "I thought all monsters were made of magic. How could it survive through the resets?" 

Sans smirked, "That's where my personal brand of magic comes in." He reached his finger out and summoned a light blue orb of light. "How much do you know about the elements of soul magic?"

"More than you'd think, less than I should," Frisk said awkwardly. "I know that every soul trait can be expressed through different elements when using magic. I'm pretty sure it's dependent on the individual, but certain traits exhibit certain elements more often." He pulled PERSEVERANCE to his right hand and JUSTICE to his left. "I know I have fire and lightning. And that light blue…" He thought for a second. "Means you have PATIENCE, though I don't know what element that normally expresses itself as."

"It's Time," Sans said simply, and Frisk's eyes widened. "It's not as powerful as you think; most people can only really use it to slow people down. Unlike your fire or Papyrus's gravity, it's incredibly difficult to intuitively control the flow of Time to Attack. It also skews heavily toward slowing Time, so it's rather difficult to do anything more complex."

"But you can," Frisk observed. From what he could now deduce, that was probably how the skeleton teleported. Some sort of controlling Time to control space business that he couldn't even begin to comprehend.

"Right on that too. I've figured out a way to store the memories in a bubble of frozen Time that can persist through resets." The light blue orb on his finger started to grow and float upwards. Slowly, it grew bigger, and Sans brought it down between his hands as it collapsed in on itself. That process continued for over a minute, and Frisk could tell it was heavily draining. 

Maybe that was why Flowey got the drop on Sans. The skeleton had just pulled an all-nighter (very rare for him) and expended most of his magic on this. 

The collapsing orb eventually stopped and seemed to freeze. Sans carefully brought it down to his machine and placed it in the repurposed chamber. 

"This is all amazing." And it really was. Frisk was fascinated by this sort of thing. He felt a bit of jealousy that he had gotten something as simple as fire and lightning before shaking that thought away. "But why would you use our limited time here to explain this to me?" If Flowey discovered what they were doing like he had the last reset, this could all be over. 

"Because there's a few cracks in this plan." Sans sighed, now suddenly exhausted. "So I need you to fill those in with your ability to remember the resets passively. Think of yourself as Hematoma." Frisk didn't know what that was. Was it something to do with blood?

"There are three problems. I only regain these memories when I absorb the stored magic, which means I have to come down here and purposely check the machine. So you'll need to somehow get me to do that before I can be useful." That did make sense; when Frisk had met with Sans earlier in this reset, he didn't think the skeleton was aware of the situation. "This also ties in with the second problem. I only remember what I put into the saved memories, so if I'm ambushed, I'll need you to fill me in on what happened."

That made sense, but… wait. "But you got ambushed by Flowey earlier. How did you know what happened?" 

"I planted some magic on your shoulder when I teleported behind you. It wasn't much, but it gave me a good idea about what happened." He held up his hand, and it glowed blue.

Frisk hadn't even suspected something like that. Was there a way he could learn to sense magic?

"Moving on, the third problem is the most important. The stasis field is imperfect and degrades when experiencing a reset. If this flower resets too many times in a row, it will drain the magic until nothing is left for me to absorb. Based on current trends, I would have to recharge the magic before 6 resets for that to happen." 

That… wasn't good. If Frisk got into another big fight with Flowey where the flower used resets to try to win, then Sans wouldn't remember anything. "In which case you want me to explain all these things to you to replicate the process." That was definitely some good foresight. "Is there any way to improve that number?" 

"Not easily." Sans grimaced. "I can maybe get a bit better at putting the magic together, but what I really need is a good container for it." 

Frisk thought back to that repurposed internal battery storage and then to all the items he had on him before the resets. "But anything you created now would be destroyed by the resets." Sans nodded. "Maybe you could find some way to extend the stasis field to objects?" He considered.

"I'll certainly try, but it's difficult for things to do their job while frozen in time." Ah, that was embarrassing; of course, Sans had already thought of that. Frisk doubted his half-remembered science classes could compete with a person creating some sort of wormhole. 

After they finished that conversation, it rapidly approached the point where Flowey would become too suspicious of their whereabouts. Sans quickly gave his secret code word to check for time travelers because he apparently had one of those. It should give Sans the excuse to check the time machine after meeting the first time.

Then, they quickly discussed what they could do moving forward. Frisk shared some of his future knowledge, especially the part about Alphys and her lab; though Sans seemed to know something about that, they didn't exactly have much time to discuss it. 

Frisk asked Sans if he could build some sort of time-based weapon to kill Flowey, but they both agreed that would have to be some sort of last resort. If the skeleton showed any knowledge of Flowey's true powers, they probably wouldn't get another chance to stop the flower. 

Eventually, they decided on a wait-and-see approach. They both agreed their best bet was to lie low until reaching the lab and then figure out something from there. This meant Frisk would have to get there, past Undyne, without Sans' help.

"I'm fairly confident in my JUSTICE. I should be able to flee until reaching Hotland." Frisk said, explaining the plan he would have used before the skeleton interrupted him. Though now Sans had an odd look on his face. "What?"

"I've seen your JUSTICE during the fight with my brother, and I think you might be underestimating Undyne." Ah, even Sans thought he was too weak. "But, I doubt it's anything a legendary teacher like myself couldn't fix." 

"Really, you'd train me to use JUSTICE magic?" He hadn't expected that. "And wait, legendary teacher?"

"Technically, everything that can happen has happened, so I'm sure someone's called me that before." Sans reached up and grabbed Frisk's shoulder again to get ready to teleport. "And I think I'm fairly good at using it myself." His one eye flashes yellow. 

Frisk rolled his eyes. "That just makes me doubt your teaching ability. Were you the one to teach Papyrus how to cook spaghetti?" 

Sans looked at the wall where there was definitely not a clock. "Oh! Look at the time; I think you're late for the date with my brother." 

Frisk sighed. "It's not a date." In a flash, they were somewhere in the snowy woods. "Were you the one putting weird ideas into-" And Sans disappeared before he could finish. 

At least that teleporting was on his side now.

"My RIVAL! You have finally arrived to challenge me!" Papyrus's voice called out from behind him. 

A/N: Aloha! I don't know if this chapter came across as dry explaining, but I had a blast writing it. I hope you liked some of my explanations and devices I've set up for this story in the future. I'll answer any questions in the comments that don't massively spoil the story.

Announcement! I've started a for now completely free Patreon account. It's under my account name Tempest2077 and has nothing that requires you to pay, though I might have some in the future. For now, it will have chapters of both my original story and this one coming out one day early for everyone at no cost to you. That means the next chapter of this story should be available over there right now.

Don't worry; pretty much everything I put up there will still come here and be available for free. I just wanted to do some extra stuff over there. Here are some things that might be coming.

Repository for all my stories from different platforms.

Character sheets and other bonus stuff: A Sans character sheet should be out right now.

The ability for polls on what story I write for next: I've also been thinking of continuing some of my older catalogs.

Early access to chapters up a week early: It will probably cost like 2 bucks or something. (Upcoming)

I just thought this could be a fun thing and give me more motivation to write better and more. There's absolutely no requirement to go there. This is just for those who like this story and my writing.