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WHUMP!
The ceiling of the barracks' training hall stared blankly at the scaly blue face staring back at it. A blue spear on the very edge of her field of vision was already dissolving. A wave of aches and pains washed over Undyne, her body and subconscious more willing to acknowledge the end of the battle than her waking mind ever would be.
"Are you alright?" asked that deep voice yet again.
"Mmh," she grunted.
"Good."
It was the longest the teenager had lasted yet, but it wasn't enough. Even as she already began her post-spar ritual of reviewing the fight, looking for signs she'd pressed Asgore any harder, any sign of fatigue or weakness, she already knew there wouldn't be any. It felt like the stronger she grew, the harder she fought, the fiercer he fought back. Frustration bubbled in her stomach as she noticed a patch of the ceiling that needed painted. Frustration was no stranger to Undyne's stomach as she continued to lay on the training mat, but a much more bewildered emotion to find itself there was doubt.
"Your form has improved," said Asgore, still not view from where she lay. "No doubt you've been drilling at home again."
"Mmh..."
Had she ever seen Asgore's peak? Would she ever see it? Every clever feint parried with deceptively fast shifts of his stance. Every direct blow met and returned with refined brute force. A question refused to leave her head. She wanted to get up and yell at him. Tell him what a waste of time this was. To then round on herself for being a quitter. Then to break something, preferably expensive. But first of all, she wanted to curse.
"Would you like a cup of tea?"
...or that. She wanted that. "...yeah."
The tea dampened her frustration, but did not wash it away. Soon she tried a second drink, colder but more energetic.
"Well ya knew what you were signin' up fer, kiddo," chuckled Gerson, adjusting the oil lantern hanging over his counter.
"I thought I did," said Undyne, gripping her glass with enough concentration to avoid accidentally crushing it, "and he's always teaching me stuff even when we aren't sparring, so no it's not a total bust. But... when?! When will I beat him? I don't see an end to this!"
Gerson sat back down on his armchair, his leathery finger playing with his wisp of a beard. "You gonna point somethin' dangerous at me if I hazard the word 'patience' in this discourse?"
The look in her single yellow eye admitted the thought occurred to her. "I know I'm getting more skilled. Heck, I'm getting stronger. When I train by myself at the barracks, the weights get lifted easier and the dogs lose to me faster. So I'm not crazy, objectively I can kick more ass every day."
He poured his third glass of Sea Tea, his own yellow eye not meeting hers. "...butcha don't feel it. Cuzza Fluffybuns."
Her fist slammed on the counter, causing Gerson's hat to slip off in surprise. "Exactly! Every step of progress I take, it feels like he takes two! Okay, maybe a step and a half, but..." Her growing snarl melted away as her thoughts flowed to a place she felt out of her depth probing. "Is it because he doesn't have a kid anymore? The way Boss Monsters work, maybe they just build up power forever without lifting a finger...?"
Gerson continued not to look at her as he retrieved his hat. "Nope. May look infinite to you, but he's got limits. Those limits don't really change in... in his situation."
Undyne wasted no time fleeing the subject. "Then is he just toying with me?"
"Missy, d'ya think you'd be sittin' here if he went all out on day one?"
It didn't take her long to say. "No, if a fraction of what's said about him is true, I'd have been dust years ago."
He nodded sagely. Or at least, he hoped he had practised it enough so it looked appropriately sagely. "Gettin' stronger takes time. An' no, I don't know how much. Just keep on keepin' on. 's all I can tell ya."
They both knew this was the likely outcome even before Undyne greeted the old turtle as Leatherhead. She looked down at her cup. Gerson looked over at a dusty box full of emblems. Neither noticed the pensive expression on his face.
"...what if I'm just not strong enough? Not just to beat Asgore. When the humans come with their mind powers and threaten a little kid... If I go down in one hit, who will...? Maybe he's wrong. Maybe I'm wrong..."
A low antiquated sigh filled the air. Undyne looked up to see the tough shell of the storyteller. She couldn't tell what he was thinking. Before she had a chance to ask, he swung round, the biggest crooked grin on his beak-like mouth.
"Hey kiddo," he said, "I ever tell ya 'bout aquatic monsters on the surface?"
Undyne blinked, absently rubbing her eyepatch. "No. Why...?"
"Well I say 'on the surface', but you didn't see much of 'em out in the sun. Fishies like you liked water, no duh. Livin' at the bottom of lakes an' rivers an' junk. Officially they answered to the King, but most've the time they did their own thing. Wasn't 'til the war got them off their soggy duffs to help us out that I saw more th'n a dozen on dry land! And boy howdy did they complain, I remember this one guy yappin' about how itchy his-"
"They didn't do any acclimatisation training? At all?"
Gerson blinked this time, retreating from his tangent. "Nope. Concept was utterly alien to 'em. Figured they'd always have somewhere wet to go. It was the same once we got chucked in here. Waterfall was always their turf, why wouldn't it be, y'all don't do that well swimmin' in lava. Wa ha!"
Undyne looked at her hands, taking some satisfaction in doing something her ancestors never did. "So they lived here. So what?"
"Well, I say 'here'..."
Gerson watched her eye dart around, processing his implication. She caught on surprisingly quick.
"The river? They all lived in the river?!"
His grin broadened. "Not quite the river proper. All that icemelt from Snowdin, way too cold fer most. But there's some underwater caves underneath Waterfall. Whole honeycomb of 'em. Warmed by proximity to Hotland. If yer only experience with dry land is gettin' whipped by humans, you go back to what worked before, right?"
"I never thought..."
"Well there's a surprise, ha!"
She took the barb in stride. "Lots of aquatics sleep in pools and ponds round here, but they hop out to go to their jobs most of the time. You're saying a lot just stayed down there in, what would you call it, lower Waterfall?"
"Yep! A right pain in Asgore's buns when he needed a word. If it weren't fer fire magic he'd still be damp today."
"Do they still live down there? I've never been-"
He shook his head. "Wasn't a big calamity or anything, far as I know. Times moved on. Kids of kids of kids didn't have the same need to keep their distance. Eventually most took to workin' with lungies. Cultural shifts lessened the differences between monsters, 'specially when each other was all we could rely on. Heartwarmin' in a sense, comin' together after a crisis. Even if it took a century or two."
She nodded in an adolescent facsimile of sageness. "I'm glad aquatics decided to do that. Imagine if I never thought to pick a fight with the king."
"The world would truly know peace then, wa ha ha!"
"Fuhuhu..." It was Undyne's turn to grow pensive. "Why are you telling me this? I mean it's cool and all, but..."
Gerson's grin withdrew from his face. Undyne had the impression he was reluctant to answer. But then...
"You live apart from your kin since time immemorial, you find different ways of doin' things. Didn't see much of it myself during the war, but there were stories..."
"Stories of what?"
He took a deep breath. Like he was bracing. "Most monsters just fight with magic, right? Or any sharp appendages they happen to own?" Undyne nodded. "Well on the- just beneath the surface, aquatics used their magic to create tools. Tools that amplify their magic, mebbe even give 'em abilities they didn't otherwise have." He played with his beard again. "Make 'em... stronger."
He wasn't looking at Undyne, but could feel her eye piercing him with its intensity.
"Did... did they bring anything like that with them when we got banished?"
Gerson shrugged. "Ain't like we had a luggage manifest to check! But there were some noble lordly types, almost thought of themselves as Kings beneath the shores, very stuck up. If anything like that made it down here, it'd be theirs..."
"Where?"
It was a perfectly polite question, and that's what scared Gerson. He looked into her face. He'd seen that face once before, when she'd nearly knocked him over telling him Asgore was going to train her. It was too late for reluctance now.
"Go to the pier south of yer house. Swim east. Entrance should be half a league or so. Can't say much more, I dunno who lived where."
"Cool! See ya!"
"Now hold on, missy!"
The tone in his voice stayed her hand from grasping the door handle. She turned back to see him standing as upright as his back allowed, an air of authority that sometimes threatened to appear on Asgore's face.
"...tomorrow," he said, "wait 'til then, an' I'll go with ya."
"You will?"
He nodded. "Ain't gonna get the blame for you goin' off an' gettin' lost. Not without havin' a little fun, anyway!"
Undyne pumped her fists, delighted at tacit permission from an adult to do something dangerous. "Awesome! When should we head out?"
"Oh, say mid-morning. Maybe after lunch. Been a while since I went after the early worm."
Delight turned to 'Delight'. "Uh, sure. See you at the pier then."
Undyne did not see Gerson at the pier the next day. Because she was there five hours early.
"How hard can it be?" she asked herself for the dozenth time. "And why wait?" That was the twentieth.
"Because I do not run a service before this hour, child," answered the hooded figure aboard the boat waiting for her to step on.
"I wasn't talking to you," she snapped. "And I'm not using you today. So, um... skedaddle. Please."
"To skedaddle is not to skedawdle. Tra la la..."
The boat unmoored, and raced away towards Snowdin. After its ripples died down, she looked past her bare webbed feet to the glass-like water. It looked calm. Deceptively so. The current wasn't the fastest, but to swim against it was almost inevitable defeat. Someone not biologically or thaumaturgically designed to thrive in water might have hesitated. Undyne wouldn't have even if she wasn't.
"Let's go!"
She dove in, leaving the smallest of splashes behind her. She took to the environment like a Her to water, quickly picking up speed and taking a moment to revel in how to maneuver with a third dimension. The shallower pools of Waterfall never had the kind of depth to truly revel in how fast she was. The water felt colder than she was used to, albeit it had been a while since she'd swam for so long, but it wouldn't be a problem unless she decided to go to Snowdin. Thankfully her goal lay in the other direction.
Her webbed hands propelled her forward like a spear through a training dummy. Her feet didn't kick as a human would however. Instead they clung tightly together, waving back and forth like a fish tail to help give her further momentum and stability. Her single eye gazed unblinking through the dark waters, feeling them warm slightly as she grew closer to Hotland.
"Ah-ha!"
Her voice, oddly echoing under the water, carried quite well regardless, and anyone with language could have understood her. A quirk of the magic that made up her soul. And her exclamation was because she found what she was looking for. In the walls the river coursed through, an opening approached, mageweed threatening to cover up the Delta Rune carved into the rock above. Clearly monsters had been here before. The sudden rise in temperature as she swam into it was practically a sign of welcome, already clear of the icemelt. Stage one had gone without a hitch, now to round this bend and begin her-
"Glub?"
"Ah!"
A spear flashed into existence as Undyne found her path suddenly blocked by a large opponent. She pointed it at the intruder's safari jacket for several moments before realising who it was.
"Gerson?!"
"Glub," he said. "Gurgle gleugh garg glub, glub?"
Her eye narrowed. "Uh... what?"
Gerson blinked unnecessarily. Then a leathery hand grasped his throat. It glowed bright green for a moment.
"That's better," he said, his voice as echoing as Undyne's. "Knew I forgot somethin'. But I didn't forget how stubborn you were. Wa ha ha!"
"Damnit, who squealed?" demanded Undyne. "Was it Jerry? I knew I shouldn't have bragged to him!"
"Good bet, but no," said Gerson. "My ears may be on strike most days, but it ain't hard to hear someone yell 'Why should I wait on that old leatherhead, I'll just go first thing.' from behind my door."
"Oh..."
In her sheepishness, Undyne took Gerson in. His legs kicked calmly but confidently in the quiet waters of the cavern to keep him sinking to the rocky floor. He seemed larger than she ever remembered on land, not as large as Asgore but looking down on her for the first time in years while their feet were level. She realised he wasn't bent over as much, the reduced strain of gravity allowing him to bare his shell with ease. In one hand he held the lantern he'd fiddled with yesterday. Its flame shone brightly, despite its housing being completely flooded. It must have been a gift from Asgore, fire magic didn't care about mundane water.
"Welp," said Gerson, "I said I'd take ya, an' here we are. You wanna continue?"
"You mean," she said, gripping her arm, "after I disobeyed you and...?"
With his free hand he tussled her hair floating freely in the water. "Ain't like I'm yer superior officer. And unlike young Jerry I ain't a snitch, unless it's really embarrassin' and funny. So, shall we hence, Kiddo?"
"Heck yeah!" She swam round him and down the tunnel. "Keep up, old man!"
Gerson hung his lantern on the pickaxe sticking out of the backpack on his shell. "Careful what ya wish for..."
Undyne's idea of a measured pace of swimming would have exhausted most triathletes, but it wasn't enough to leave Gerson behind. Despite his body being less adept for aquatic maneuver than Undyne's, and his strokes being not as hard pressing as hers, she found he kept pace with her without much effort. Fuzzy memories of a story about being slow and steady came to mind. To retain some superiority she swung round under him and looked up at his face, propelled forward only by her legs.
"You're pretty good," she said, grinning through razor teeth. "Are you actually an aquatic monster?"
He shook his head. "Gotta use breathin' magic down here, unlike you. Not all water-friendly monsters are outright aquatics though. We Booms are very swimmin'-adjacent, even if I personally prefer a dry bed to sleep in. I remember my grandpappy saying once he took a swim round an island an' saw a human naval fleet in a storm, an'-"
CLANG. "Argh! Sunuva-"
Undyne clutched her head as she drifted back from what she'd crashed into. An iron lattice criss-crossed the tunnel, twelve bars vertically and seven horizontally, blocking further progress. There were no obvious handles or hinges to suggest it was a gate one could open.
"How rude," chuckled Gerson, "not lettin' any old sod jus' waltz in an' peek through their windows."
"Yeah, the jerks," snarled Undyne, missing the sarcasm with her headache, "how are we supposed to get past?" Her first instinct was to strike it with her spear, but it made an oddly musical *tink* noise and did little else. Then she tried squeezing through the gaps between the bars, but could barely get one shoulder past. Then she cursed, and to her amazement, nothing happened.
"A royal guard knows when not to go all out," said Gerson, in a rote recital. "Lessee here..."
Undyne swam aside to let him examine the metal more closely. He grabbed his lantern with one hand while the other delicately tapped on the lattice. He squinted, looking for some inscription or weakness that could allow progress The taps almost sounded musical as Undyne watched him tap a random assortment of intersections in the grid, each tone sounding unique. After a while he put the lantern down on the floor, and an oversized warhammer flashed into existence, and the metal rang like an ominous bell as he struck it, knocked back by the equal and opposite reaction, his shell bumping gently into Undyne as she arrested his drift.
"Well they sure as heck knew what they were doin'! Wa ha!"
"And how does that help us?" lamented Undyne. "I can't believe we're beat by the first hurdle. Damnit!"
In frustration her foot knocked over the lantern, the strength of her kick dampened by the water resistance. The magical flame continued to burn, unworried about its new angle. At that moment, the light upon the floor was joined by a second one right next to it.
"Now there's somethin' ya don't see every day. Because you ain't down here to see it."
The two of them almost flipped upside down to look at the second light. It was a lump of crystallised coral, reflecting and refracting the light from the lantern. This close they could make out beams of light shimmering in the slight current of the tunnel, and their eyes followed it from the coral to...
"Eh... my readin' glasses is in my pocket, does that say anythin'?"
"It does," said Undyne, frustration vanquished by progress. "'D4... D4... D5... A4'... And what's that mean?"
"You think I got a book on subaquatic cryptography?" asked Gerson. "Wait... maybe they're coordinates..." Returning to the lattice, his finger counted four bars along, then four up. "Maybe this is D4..." He tapped the intersection, producing another almost musical note. Then he tapped it again, then the intersection one row higher, sounding a clear octave higher, then the first intersection on the fourth row.
And nothing happened.
"Hmmyegh," he grunted, less than satisfied. "Of course they wouldn't make it that easy..."
"Wait, Gerson," said Undyne, face twisting in thought, "tap that first one again."
"Huh? Okay..." he obliged, watching her tilt her ear towards the lattice as the sound rang out.
"...E-flat..."
"E-what? Wha's-"
"That's E-flat," she repeated, "at least on a piano. Those aren't coordinates, they're musical notes! Let me..." She gently pushed him aside and tapped an intersection on the leftmost bar. "As I thought, that's C. Which means..."
She counted four bars up like Gerson had, but this time only counted three along to find the first note. She tapped it twice, then the one above, then the tenth bar along on the fourth row again. As the fourth note rang out the bars, which looked completely solid before, slid into the rock as though they weren't in each other's way. Before Gerson could express a curmudgeonly impressment, his shirt was seized as Undyne dragged him over the threshold, her other hand picking up the lantern. No sooner had they crossed than the rods returned to their former position and seamlessly reformed the lattice.
"Well that's one way to keep us riff raff out," joked Gerson, swimming under his own power again.
"Good thing they didn't ask us to play something like Moonlight Sonata," said Undyne, swimming alongside her mentor.
"Why, ya don't know how to play that one?"
"Oh I do, but it's boring!"
They followed the tunnel as it twisted one way, then the other, and it wasn't long before both of them had lost any sense of where they were in relation to Waterfall or the wider Underground. Only the gradual warming of the waters hinted they were closer to Hotland. They eventually reached a long straight section, with more evidence of the rock being manipulated by tools or magic to facilitate this.
"Hey, I think the tunnel opens up down there," said Undyne, "maybe we're near the end, let's go and-"
A hand grabbed her ankle roughly. "Hold yer horses, missy."
"What horse? Aaron's not here."
It was Undyne's turn to be pushed aside as Gerson held his lantern up. Two spots in the tunnel began to glow shortly ahead of the light, one in the top right and one in the bottom left of the tunnel.
"More of that coral," said Gerson, "but I reckon it ain't got a concerto inside it this time. Stick somethin' out between them, will ya?"
Curious, she summoned a spear and stabbed the spot he indicated. Before she could dismiss the exercise as stupid the spear was knocked from her hand, a second spear made of crystal erupting from the bottom left, then slowly retracting.
"Haste makes waste, as they say," mused Gerson. "This ain't baby's first puzzle. Now if we avoid crossing the space between 'em we shouldn't end up as a shish kebab."
Gerson went first, hunching as though on dry land to avoid a limb accidentally getting skewered. Not having a large inflexible shell to worry about, Undyne's crossing of the booby trap wasn't as perilous.
"I thought humans couldn't breathe underwater," said Undyne, "not without magic anyway. Why would aquatics need something like that to keep them out?"
Gerson's beard remained twisted up as he played with it. "Think this was just meant to keep other monsters out. Remember, on the surface aquatics were hardly ever on the surface. They begrudged any buttin' in on their affairs. Old habits die hard."
Evidence of intra-monster discord more serious than someone cutting in line caused Undyne to shiver. She seized on a silver lining. "I'm glad we know humans are the real threat these days. And at least it was just the one."
Gerson's sigh didn't carry very well in water, she barely heard it. Fiddling with some valves and knobs on the lantern he raised it up again. Two more spots, this time the actual top and bottom of the tunnel, lit up with refracted light. Then two more a little further. Then two more after that. The whole tunnel abounded with booby traps with no fixed pattern of angles.
"Hope you don't have anything better to do," he joked. "This'll take a while."
"Ugh," she groaned, "this is gonna take forever."
"So will gettin' strong enough to beat Asgore."
The reminder of why they were down here almost had her start to pick her way through the traps to get it over with, but she stopped. Instead she used another spear to trigger the next trap.
"Uh, what-"
"Ngh!" She seized the crystalline doppelgänger to her own spear and pulled as it began to retreat. For a moment it threatened to snap off, but refused to budge. "Hit it! Use your hammer or something!"
"My-? Oh..."
The dark green hammer smashed down on the shaft, and with a muffled tinkling noise broke the spear from its rooted position. Undyne watched the stem slip into its hole, then stuck out the coral spear. The stem reappeared, but the spear did not magically repair itself. This one trap was truly disabled.
"...how far can you throw that thing?" asked Undyne, pointing to the hammer he still gripped tightly.
"Never tried it underwater," he said, connecting the dots, "but no time like right now." He raised it to the center of the tunnel, aiming at the distant end.
"As soon as I get out of the way," she said, summoning a spear of her own and pointing carefully. "Tunnel's too smooth for its own good. Means there's a center point that every trap crosses. A pain if you're trying to avoid them. But to TRIGGER-!"
Her explanation was cut off by instinct telling her she'd found the perfect angle, so she skipped to the action of throwing it, then dropping to the floor. The warhammer flew over her head with no room to spare. The two of them watched the spear zoom down the tunnel, coral copies of it erupting like the wake of a propeller, then with a series of smashing noises the hammer knocked each spear from its fixture. In around seven seconds the two weapons had swept the tunnel clear, vanishing as they exited into the cavern beyond.
"Haste makes waste," repeated Undyne, elbowing Gerson in jest. "well you weren't wrong about all the wasted traps!"
They swam through the tunnel, Undyne taking triumphant pleasure at each broken shaft impotently trying to hinder their progress. They didn't get very far into the cavern it opened up to, but not because of a physical barrier. They just had to stop to take it all in.
"Woah..." whispered Undyne.
The cavern was taller than Asgore's castle in New Home, and around half the width of Snowdin. In each wall were rows of holes stacked half a dozen tall, some the size of windows and others the size of doors. On the floor far below them were public structures Undyne had no hope of figuring out their purpose. Gerson's lantern was no longer the only source of light. In the ceiling were several fissures which radiated a bioluminescent glow normally seen in upper Waterfall. Never one to long endure captivation, Undyne swam up to the fissures to inspect them.
"More of that coral stuff," she said, "these must go all the way to the pools up topside, reflects their natural light like a bunch of mirrors."
Gerson shrugged as he swam up to join her. "Saves on electricity. Not that you can use much of that down here."
They approached the topmost row of holes. They were sized like windows and doors for a reason. More crystalline coral acted like frosted glass, obscuring the view into the apartment. In contrast to this concealment there was no sign of doors in any of the larger holes. Either they had rotted away with the centuries, or something about aquatic culture felt their external barriers was protection enough. Besides each doorway was a square indentation, the exact dimensions reminded Undyne of something.
"Those old family crests you keep collecting," she said, "I reckon one could fit here."
"You're not wrong," said Gerson, examining the one she pointed at, "but this one looks like it weren't used. Pristine, like nothing ever had to be forced."
Undyne swam to the next apartment. "This one has cracks in it. Maybe that happened when they moved out and took it with them."
"Good thinking, missy!" Her face did not show any reaction to the praise, instead just looking around. "Something wrong, kiddo?"
"Why is this place so big?"
"Hmm?"
"I mean this house has a cracked crest-hole, and so does that one, and two or three across the street, on this level at least. There aren't that many aquatics in all of upper Waterfall today, they wouldn't fill this top floor. Why build so many houses?"
Gerson waved a dismissive hand. "Up on the not-quite-surface they took pride in their underwater dwellings, how much forward plannin' they put into it. Same thing here I reckon. Knowing there's no idea of when they'd ever breathe air again, never mind see the sun. So they took it to the max."
"I guess..." She looked around the empty town. "Maybe that's why they moved topside."
"Huh?"
"Living in a big space like this, planning for future monsters that simply... didn't." She shuddered. "Maybe it's like they built it for... for everyone outside Mount Ebott. For the ones who didn't make it. I dunno, just imagining that? This place starts to feel like a graveyard. Who wants to live in one of those?"
Gerson stroked his beard. "Huh, now you mention it, that might make sense-"
"Ngah!" A blue spear shattered a coral window, its tinkling shards barely reaching their ears.
"Woah, what the-"
"Humans!" spat Undyne. "They made this place the way it is, even if they never laid eyes on it. If they ever come back to finish us, I hope they all drown trying to reach here!"
Gerson could see the logic of her argument, even if it was as distorted as the view through a surviving window down here. He rested a hand on her brooding shoulder. "So uh, shall we see if anyone left any tools behind?"
The brooding evaporated. "Oh yeah! Let's go!"
Aquatic households didn't put much stock in customization, it appeared. Every apartment had the same layout. There was a large communal room with another light-granting fissure, a raised slab of rocky floor that must have acted as a table, but no chairs. Floating in the water was comfort enough. There were also shelves chiseled into the wall. Two smaller rooms led away from the living room, one that Gerson surmised was a pantry and kitchen, and one that must have been the bedroom. Not that it looked like anything a lungie would have slept in. Another raised slab, but covered with a thick quilted patch of mageweed. No pillows or blankets, a resident of lower Waterfall trusted that the temperature wouldn't wildly deviate. It didn't take long for Undyne to grow frustrated with another thing these apartments had in common: They were almost completely empty.
"Damnit," she said, emerging from the twentieth one they'd searched. "I thought this would be like a huge treasure trove or something."
"It ain't like they had to flee in the night," mused Gerson, examining an old hidebound book with seaweed pages found at the foot of the bed. "They just moved away. Plenty of time to pack up most of their junk."
She clenched her fists. "Then where did all their powerups go?!"
"I've no idea how common those were," he said, trying to withdraw from her glare. "Mebbe they didn't survive the war after all. I made no promises on them, I just-"
"Then why have I wasted my time here? I could have been doing squats!"
As had become something of a ritual the last eight or so houses, Undyne threw a spear towards the ceiling, carrying a little of her growing exasperation. For the ninth time she saw it ricochet off a light-fissure and sink to the floor far below. The thought of all the houses they had yet to search threatened to instil a deep weariness in her, which perhaps was why she made the observation she did, to avoid entertaining the notion of defeat.
"Hey Gerson. Look down there."
"Wha...?"
"The far end of the cavern. Those houses look different."
It hadn't been apparent when they first started searching, but they'd progressed further along and details that far off came into sharper focus. At the top level there were no holes whatsoever, and there only appeared to be windows on the bottom row.
"Huh," said Gerson, glad of a delay to consoling a disappointed Undyne, "if it's different, there's probably a reason."
It took them a while to reach that part of the cavern, and Gerson started having difficulty keeping up with Undyne as she got closer. The windows were arranged in maybe five clusters, but the more interesting discovery were five sets of rusty iron doors.
"Doors!" cried Undyne. "The first set since we avoided getting skewered. I bet the big wigs lived here. If anything valuable is here, it'll be in one of these houses!" Gerson didn't have time to agree before she pointed to the second door from the left. "That one."
"Eh? Why that one?"
"...it still has its crest."
The natural airbreather once again blinked out of habit. Sure enough while the other four houses had cracked indentations, the one she identified had a smooth panel almost buried in muck. Gerson drifted over to it and wiped it clear. The emblem was a large green heart with a blue line bisecting it, and a four pointed golden star in the center. Undyne stared at his shell for a while, waiting for a snarky comment that never arrived.
"...hey old man, you okay?"
"Yep!" cheered Gerson, with unexpected force in his voice. "I reckon you're right, anything of interest will likely be here."
"I know I'm right, you leatherhead!" She grinned. "Now, how to get in? I doubt there's a skeleton key round here."
"You ever think of knocking?"
Undyne looked at him like he'd suggested peace with humanity. "For serious, you think I'll just go up and knock-"
She'd been following his suggestion with all the sarcasm she could muster to underline its futility. On her third knock, a cracking noise stopped her. She saw three puffs of rust emerging from the edge of the door, which promptly fell inwards with a muffled thump, throwing up clouds of debris that mixed with the diffusing rust.
"...you're welcome," said Gerson, swimming past her face still frozen in mid-scorn.
She caught up with him a brief ways in. Beyond the house's antechamber was a spiral set of stairs both concluded had never been directly trodden on. There were more crystalline coral fixtures along the corridor, but instead of being a receptacle for refracted bioluminescence, they glowed with obvious magic, not having dimmed in all this time. By the time the stairs terminated Undyne reckoned they were three levels up from the cavern floor. An empty doorway led to a room the size of Undyne's house in upper Waterfall, looking oddly shimmering. Remembering the coral spears, Undyne used a spear to test the threshold.
"Some kind of downward current," she said, "but it doesn't look like it does anything."
It was about four seconds after she entered the room she learned of her error, as the light that should have been coming from Gerson's location, and the oddly comforting shadow it cast, disappeared. The room became oddly murky with only the coral lights now present. She looked back to Gerson, looking perfectly fine, but examining the lantern, its flame finally doused.
"Must've been some anti-fire magic," he grumbled, "two ticks..." He put the lantern into his backpack, pulled out a headband with a waterproof electric torch attached to it, putting it on just under his hat and turning it on. It was bright enough, but the loss of Asgore's guiding light made Undyne feel uncomfortable.
The large room they were now in looked like a study. The first thing that drew their attention were actual chairs arranged round an elaborate crystal structure in a recess in the wall, a clear facsimile of a fireplace. Unlike the common apartments, the bookshelves were packed with books, much to Gerson's delight. Undyne didn't notice the new bulges in his backpack later. A metal shield hung above the coralplace, badly rusted but the same emblem still discernible. A small dinner table took up a corner of the large room, and like the chairs were actually like those a lungie would sit in. There were several doors no doubt leading elsewhere, but no sign of life. At least until Undyne saw a large figure in a gloomy corner.
"What's that?" she asked, pointing.
Gerson looked over, and lit the figure up. It was a marble statue of what looked like a human, well toned and with a large beard, wearing a breastplate and sandals. He was twice as tall as Undyne, so in her mind he was lifesized. In his hands he held a trident much like Asgore's, though lacking the floral adornments. She swam up to the statue and noticed the name plaque at his feet, in an alphabet she didn't recognise but refused to admit.
"Nodei... Nobeidwuv? What kind of name is that?"
"Poseidon," said Gerson, looking up at the imperious face rather than the writing. "Old Human God, ruled the seas. Always heard he had a few monster followers."
There was no sign of the mansion's owner. Undyne didn't relish the truth that if the worst had happened, their dust would have long since scattered in the slight current she felt coming from above. That was odd in itself.
"Hey, look up a moment, will ya?" she called to Gerson.
He obliged. Less of a fissure and more a full blown tunnel was present in the center of the ceiling stuck through the ceiling. Undyne swam upwards to investigate, joined by her mentor. A brief way in, their path was barred by a large boulder. Undyne could make out the glow of reflective coral through a few gaps, as well as a much stronger current.
"Some kinda collapse," said Gerson. "Would explain why it's so dark in this room. And maybe why a magical defence triggered."
"You think they hid anything valuable up here?"
He chuckled. "They'd have a hell of a time getting it back down. This is worse than gettin' down the tree every year!"
"I'm gonna find out."
"Wait, how-"
A spear, that was how. Or at least that was the idea. She launched one up, but it bounced off the boulder with no signs of damage. This made throw another one, even harder than before. The boulder continued to live its best life. Before Gerson could stop her she was up in the boulder's face trying to stab it to pieces, her curses echoing throughout the room.
"Come on come on COME ON! DAMNIT!" She began to sink back down. "This is my problem, I'm not strong enough yet!"
"Welp, casual breaking of stone ain't a standard monster talent. Lessee..." Gerson swam up to the boulder, summoning his warhammer. He swung at it with a speed Undyne hadn't expected, but the muffled thump just about symbolised what effect the blow had, a limited one.
"I bet Asgore could break it," grumbled Undyne. "Like that cave-in you told me about once. Urgh, how can I ever protect anyone if I can't even smash a stupid rock!"
"Well," said Gerson, reaching for diplomacy, "nobody expects a guard mid-training to-"
"I EXPECT IT!"
Undyne crossed her legs as she reached the marble floor of the study. Gerson allowed the current from the blocked tunnel to push him down passively, as her muttering became clear.
"...useless useless useless..."
"Hope you're talkin' about the lantern right now. Wa ha ha!" She didn't respond, so he pulled out a hip flask and took a swig. "Sea Tea? I bet you skipped breakfast this morning."
She said nothing, but accepted the drink.
"So what's it gonna take?" he asked. "A reminder of a time Asgore wasn't so badass? Heck, maybe a time early in my own career I screwed up and-"
She turned her back to him. Though she wasn't a turtle, it felt like he was looking at a shell.
"Maybe Asgore was wrong," she said. "Maybe I'm not worth all the time he's spent on me."
"Not like he's running short on time to spend."
"Yeah, but... maybe if I wasn't distracting him or something he'd figure a way to break the barrier. I'm just holding him back."
Gerson tilted his head. "Kiddo, you can't even stay in Grillby's durin' happy hour yet. Take it from me, you ain't peaked yet. And if you weren't divestin' him of his time the only net change would be more flowers around the throne room."
She still had her back to him. "...is that even possible?"
"If it is, he'd find the way to do it, heh heh!" He patted her back, relieved she didn't flinch. "You know Captain Argie?"
She slowly turned to face him."Well yeah, he's Captain of the Royal Guard. Finest warrior Underground who isn't also an old fart."
He nodded. "I appreciate your candour."
"He mainly tells me to make sure my armour is well cleaned and ready for action."
"Some things never change, heh. Now Asgore didn't spar as much back then, was before the whole... prince thing..." She allowed a reverent pause in the story. "But young guards always have somethin' to prove, so they take a swing. And none of them laid a finger on his buns. Sound familiar?"
She gritted her teeth. "Yeah..."
"And he never invited them for private lessons or anythin'."
Her eye widened. "Really? You really think I'm the first-"
"Well not literally. Back when we were first down here and had a million things to do, he helped train new recruits to get them up to speed. But since then, he always delegated trainin' to whoever was captain. But you're the first since then. You know how Argie got the job?"
She opened her mouth to speculate, then closed it again. "You're gonna disabuse me of how it wasn't some of feat of strength."
He looked impressed. "You're learnin'. There was a building collapse, near where the Core is. The guard was mobilised of course. He didn't dramatically defeat a pile of rubble or suplex a boulder just because he could. But he kept goin' back into the wreckage. Pullin' survivors out. Keepin' dust together. Other guards took breaks, even if they had to be ordered to. Argie refused. Not until everyone was accounted for, better or worse."
Undyne nodded approvingly. "He never gave up. I can see why Asgore would like that in a captain."
"Wasn't just his can-do attitude, though. Everyone he brought out either had a bed and a warm drink, or consoling words for their families. Guards have always had to go after trouble, but the ones that stand out best in this old noggin are those to focus on trouble's victims. Makin' 'em whole where possible might be more important than brute strength. An' Argie never did lay a finger on Asgore, even after he got the job. Maybe the time he invests in you is worth it if you remember all that."
Undyne didn't respond, but instead took a drink. She still felt like she was better suited to fight trouble than clean up after its mess, but Gerson's words were taking root in her head. Maybe...
Something landed softly on her head. Confused, she reached for it and found a small stone in her hand. Looking up, she saw more where that came from, namely the boulder which had finally wrenched itself free thanks to their efforts and was falling as if through air.
"Oh crap crap crap MOVE MOVE MOVE-!"
"Wh-"
There was no time for vowels. Gerson was shoved into the coralplace with amazing speed, but Undyne didn't join him as the boulder crashed into the floor, kicking up a lot of dust. Unsatisfied with its progress, the boulder rolled away from them towards the stairway door, crashing into it, and blocking it almost completely. The calamitous cacophony took its sweet time being replaced in his ears with growls of pain.
"Undyne!"
She'd successfully cleared the main boulder, but several smaller rocks had fallen in its wake, and one had pinned her by the leg. As per her training she didn't struggle fruitlessly and exacerbate the injury, but was running her mouth, the best anaesthetic she had on hand. A leathery hand rested on her chest, and she stopped cursing. With his other hand he pushed the rock aside, and looked at Undyne's leg, bent in awkward angles.
"You okay?" She nodded, not trusting her mouth to bite his head off. "I got a splint in here..."
It took him fifteen minutes, but the leg was now strapped to a shaft of wood and mostly straight. Undyne took his offered hand and lifted herself into the open water, experimentally swimming around with her hands and the ungraceful kicks of her good leg. She could move under her own power, but it was slow.
"Just great," she yelled, mostly at herself, "I'll never hear the end of this from Doctor Drake!"
"We'd need to get topside fer that," said Gerson, lacking his usual jovial air. "Think that boulder got any more fragile?"
He pointed to where the stairs and the dousing downpour had been, now replaced with the latest fashion, rock. Undyne immediately summoned several spears to launch at it, but it was good hygiene off Jerry's back. Gerson was unnerved by the raw desperation on her face. This had to be her worst nightmare, being inadequate in an emergency. She clumsily made her way over to look for gaps they could exploit.
"I might be able to slip through here," she said, pointing to one such gap, "but it'd hurt like hell. And you wouldn't fit with that shell, so you'd be stuck here. I'm not leaving you behind."
Gerson recognised that matter of fact tone from Asgore. He would be more polite in using it, but it was dangerous to argue with him with that voice. "Okay, lemme..." he swam up towards the now clear tunnel shining reflected light into the room, but his progress slowed at the very edge. "Current's weirdly strong, dunno if I could push through. An' I dunno how long I'd have to do it for."
"I could have half an hour ago," said Undyne, bitter at her responsibility for this disaster.
"Hey, the trident."
"Huh?"
He pointed to the statue, now more discernible in the light. "Maybe we can use that and my hammer as a lever to push the boulder away."
A plan of action was the best queller of self-doubt. "Okay, let's do it." She grunted in pain with every stroke towards their best chance. "Now you may need to break this guy's arms off, don't think he'll let go-"
As she grabbed the trident, it suddenly glowed the same colour as her spear. In defiance of her prediction Poseidon's hands moved, releasing the trident and threatening to drag her to the floor with its weight. It shone even brighter though, and through the glow Gerson had the impression it was shrinking. Almost as soon as the glow had begun, it ended. Gerson looked at Undyne, now wielding a trident appropriately sized for her, its austere marble replaced with crystalline coral. Her eye moved up and down the weapon, trying to comprehend what had just happened.
"...the pain's gone."
Before he could stop her, Undyne ripped off the bandages around her leg, letting the splint fall to the ground. If it wasn't for her badly torn trousers, her leg looked perfectly normal. She swam a little, her mobility restored.
"What the heck what the hell what the crap?!" she exclaimed.
"...I think," said Gerson slowly, "we found what you were lookin' for."
Disbelief was etched on her face, and yet she gripped the trident even tighter. As thought she'd known all along what to do, she held it out with one hand. Her blue magic enveloped it, forming a trident not unlike her spears, then streaked across the room towards the boulder. The crashing noise was no longer muffled by the water, it was clear as air as the boulder shattered into pebbles, Undyne having her revenge against the natural object she'd recklessly provoked.
"This is... SO COOL!" Her grin threatened to consume her whole face.
Gerson was lost for words to describe the amazing feat she'd just achieved. "Looks like the path's clear, we can get back out-"
"Wait," she said, turning around, "I wanna figure out what else-"
"Woah!" Gerson was suddely pushed back in the direction her trident had moved as she turned.
"What happened?"
"I dunno. Felt like a sudden riptide..."
Understanding erupted on Undyne's face. Instinctively knowing what to do, she pointed the trident at one of the chairs. Gerson just made out the new flow of water that pushed it over.
"Why go back the way we came?" asked Undyne. "C'mon, grab my leg."
Hesitantly, Gerson did as she said. She raised the trident skyward, and they rose, despite neither of them making any movements that looked like swimming. He began to feel the current that had threatened to trap them a few moments before, but this time they weren't slowed down at all. At first his brain thought the trident was pulling them through the water, but then he realised Undyne was using it to control the water, defying all natural tendencies of flow to move in the direction she wished.
"Now we're suplexing boulders!" She roared in triumph.
The tunnel was the brightest one they'd been in their whole time down here, and they could see branching paths and more coral reflecting the light from above to all the residences of lower Waterfall. Even through they were moving far faster than they could have swam, Gerson only felt the slightest current in opposition, like they were in a bubble of still water Undyne was moving. The tunnel twisted left and right, up and down, far more than the entrance did, since this tunnel had not been intended for egress. It seemed to become brighter and brighter as gradually they ascended, the temperature of the water cooling as they left Hotland's influence. Eventually it went straight up. And then it opened up into a lake bed, the bioluminescent surface of the water almost blinding after hours in the murky depths. At last, their heads broke the surface, their faces quickly feeling dry after being submerged for so long.
"We made it!" cried Undyne.
"Gurgle glub glargh," said Gerson.
"Huh?"
He blinked, this time from necessity, and clutched his throat again, briefly glowing green. "Sorry, forgot to turn it off."
They swam over to the bridge crossing this cave and climbed up. Undyne had to help Gerson reacquaint with his actual weight, as there weren't any steps to help him onto try land. Once he was out of the water, she immediately returned her focus to the trident, moving it this way and that, getting a feel for its heft in the environment she'd most likely be using it. It didn't feel much heavier than her spears. She could work with this.
"Now... let's see what you can do."
She struck the ground with the base of the shaft. Five tridents materialised above her, and with the slighted movement of her head shot off in that direction. They sliced into the rocky wall, large chunks splashing into the water below. Gerson could feel her smile grow even if he didn't see her face. She wasted no time on the next test, pointing the prongs at the water. As she expected, at her mere thought a column of water rose and broke away, floating in the air. She screwed up her face in concentration, and the column twisted shape. A sphere, a triangle, the Delta Rune, her own face, then a curse word.
"Oh that's useful," she said. "I wonder..."
Much of the water fell back into the lake, leaving a small sphere. The sphere was squashed until it was a disc. Gerson could now see her delighted face reflected in it with a mirror's perfection. Without warning the disc dived through the bridge, then up again a little further back. The section between these fell into the water, leaving a gap just too wide to comfortably step over.
"Holy moly that's sharp," she laughed. "And what about brute force...?"
Another column rose from the lake, then bent and charged into where the tridents had struck earlier. The roar of rushing water echoed long after it stopped. Gerson and Undyne looked upon the new cavern she'd just punched into existence. There was one final test, one Undyne instinctively knew she could do with this weapon. She concentrated once more, and another sphere appeared, this time from seeming thin air. Whether it was literally conjured from nothing or taken from local humidity, neither of them could tell, but Gerson watched as Undyne manipulated this body of water with even more precision than the first one. He whistled his sincere amazement.
"Boy howdy," he said, "you didn't come away empty handed!"
She turned to face him, her grin irrepressible. "Heck yeah!"
"Long as you hold on to that thing, you'll beat Asgore, no sweat. He won't stand a chance."
Her grin continued, even as her eye moved down to what she held. "...you really think so?"
"I know so. That's Boss Monster level shenanigans you can do now!" He turned around, starting to hobble to the town nearby. "Now let's get dried out, an' you can let me know when you train with him next, I ain't gonna miss seeing you kick his-"
Splash!
The noise turned his attention back to the new gap in the bridge. Undyne still stood there, but the trident was gone. Gerson noticed ripples in the lake beneath the new cavern.
"What just..." He blinked repeatedly. "Did you just..."
She planted her hands on her hips. "Yep!"
"Why?! You were way stronger with it! I thought you wanted that!"
Undyne shook her head, still grinning. "I wasn't any stronger. It was strong on its own. That's not the same. It would just be a crutch."
"B-but," he struggled, "you were so desperate..."
"I was," she admitted, "but relying on a magic tool is a dumb idea. If I get too reliant on it, and it ever gets knocked out of my hand, I'm defenceless. Better I rely on power that I can control!"
The cavern was silent for the longest time. Then Gerson burst into laughter.
"Waaaaa ha ha ha ha ha! If that ain't the most thinkin' I've seen you do in years!"
"It wasn't really that hard," she mused. "Those powers were awesome, but... all the time Asgore's spent training me? I wanna beat him square."
Gerson tussled her hair, leaving it rather jagged due to how waterlogged it still was. "Been a while since I experience anyone bein' so true to themselves, Kiddo! Guess I'll just have to wait for when you knock me over in a hurry to brag about how you whupped him."
"Yep!" She punched him in the arm as if to seal the pact. He gripped it tight.
"Now let's seriously get dried out before I catch somethin'."
He let Undyne lead the way, because it had been a long day and he was tired. Not long after they left, a yellow bird fluttered in, regarding the disproportionately small gap with keen interest.
WHUMP! Oh, the ceiling had been painted. Good.
"Are you alright?"
The waves of aches and pains were almost comforting. "Mmh."
"Good. Your form has improved."
She knew it. It was the longest she'd lasted yet. "Mmh."
"Now, would you... would you like a... cup of tea?"
The pauses caught her attention. "You okay, Asgore?"
"Oh yes, just... a little winded. No doubt I was... gardening very hard this morning... before you came. Now, tea?"
Her smile broadened. Slow and steady. "Yeah!"