Archive of Our Own

"Holy-moly!" Jaehyun called out, his voice crisp and carrying effortlessly across the bustling concrete plaza outside the entrance of the National Seoul Aquarium.

"Guacamole!" about twelve voices scattered near the front shouted back. The rest of the KOZ Elementary second-grade class was heavily occupied. Minho was aggressively attempting to stomp on a sidewalk crack to see if it would ‘make lava erupt,’ while next to him, Jihoon was fiercely tugging at the straps of his neon-green backpack, trying to prove it could stretch into a sleeping bag.

Jaehyun didn't drop his hands. He kept his posture open, a bright, expectant smile fixed on his face as he clapped a quick, syncopated rhythm. Clap-clap, clap-clap-clap.

Half the line snapped their attention forward, mimicking the rhythm with aggressive enthusiasm.

"Eyes on the prize!" Jaehyun chanted, tilting his head.

"French fries!" twenty voices chorused this time. The pigeon was forgotten.

"Macaroni and cheese!"

"Everybody freeze!" twenty-four voices roared in unison, their bodies locking into rigid, comedic statues. One boy was frozen mid-stride, a tiny girl stopped with her hand buried in her pockets, and Minho paused with his foot hovering over the concrete crack.

"If you can hear me, touch your nose," Jaehyun murmured, dropping his volume significantly. Twenty-four index fingers instantly snapped to twenty-four button noses. The sudden, absolute silence of the plaza was a testament to the invisible strings Jaehyun held so effortlessly. "Perfect. Buddies check. Hold your partner's hand. If we stay together, we get to see the giant octopus. If we scatter, we become the giant octopus's lunch. Understood?"

"Yes, Mr. Myungie!"

Jaehyun flashed them a quick thumbs-up, tucked his clipboard under his arm, and turned toward the main entrance. He’d already done the mental headcount seven times on the bus, but as they crossed the threshold into the cool, cavernous atrium, he began the frantic scanning all over again. One, two, three, four... 

"Good morning, KOZ Elementary!" 

The voice was like a pebble dropped into a still pool—clear, resonant, and remarkably gentle. It cut through the ambient roar of splashing indoor waterfalls and the chatter of tour groups instantly.

Jaehyun’s head snapped up, the number fourteen dissolving entirely from his brain.

Standing beneath the massive, suspended skeleton of a blue whale was their assigned tour guide. He wore the standard navy-blue aquarium polo, but it was customized with a single, thick, sea-foam green lanyard that was absolutely weighted down by dozens of enamel pins—glittering manta rays, cartoonish hammerhead sharks, and a tiny, blushing sea anemone. Clipped to the bottom, his official employee ID was encased in a custom acrylic badge holder shaped like a chubby, smiling beluga whale.

The sight of his face made Jaehyun’s grip tighten on his clipboard until his knuckles turned white.

He possessed a striking, almost delicate kind of symmetry, framed by soft dark hair, but the real hazard was his smile. It was incredibly wide and bright, pushing his cheeks up until his eyes crinkled into two perfect, stunningly clear crescent moons.

"Welcome to the deep sea," the guide said, tilting his head down to address the kids, those crescent eyes narrowing with genuine delight. "My name is Leehan, and I’ll be your captain today."

A little girl at the front of the line, ‘Yuna’ as her neon pink nametag read, took a step forward. She was wearing a bright blue dress covered in tiny, cartoon clownfish, and she was staring intensely at the beluga badge holder. "Can we call you Hannie instead? It matches your whale."

Leehan didn't miss a beat. He dropped smoothly into a crouch, bringing himself right down to her eye level, his smile widening. "Hannie? I actually like that a lot better. Captain Hannie it is. And I love your dress, by the way. Are those Ocellaris clownfish?"

Yuna nodded proudly, her chest puffing out. "They're Nemo fish."

"Very accurate scientific classification," Leehan chuckled softly, the sound melodic and warm.

Jaehyun cleared his throat, desperately trying to swallow down the sudden, ridiculous flutter that had just taken up residence in his chest. He stepped forward, putting on his best, most professional 'Group Leader' persona, though his heart was currently attempting a solo sprint.

"Hi," Jaehyun said, extending a hand. "I’m Myung Jaehyun. The teacher." 

The guide turned his full attention up to Jaehyun, his grip warm, firm, and lingering just half a second longer than a standard corporate greeting as he stood back up to his full height. "Ah, Mr. Myung. The front desk told me I had a legendary group coming in today."

"It's Mr. Myungie, actually!" Yuna chimed in loudly from the front of the line. She crossed her arms over her clownfish dress to correct the captain with absolute authority, then dramatically pointed a stubby index finger at the neon-yellow sticker slapped onto Jaehyun's chest.

Leehan’s gaze followed her finger, his lips twitching.

Printed in neat, professional black marker was MR. MYUNG. But right next to it, squeezed into the remaining margin in a shaky, aggressive purple crayon, was a very prominent -IE. Below the modified name was a highly questionable crayon drawing of a cat that looked suspiciously like a potato with whiskers.

"Eunji held him down on the bus so I could finish writing it," Yuna added helpfully, nodding over her shoulder toward a tiny girl with braided pigtails who proudly gave Leehan a double thumbs-up.

Leehan’s eyes danced with absolute amusement as he glanced from the smug second-graders back up to Jaehyun, a teasing tilt to his lips. "Ah, my apologies. Mr. Myungie."

A sudden, quiet spike of heat bloomed along the tips of Jaehyun's ears at the casual way his playground nickname slid out of Leehan's mouth. He squeezed his clipboard a fraction tighter, clearing his throat to steady his voice before his regular teacher persona could completely slip away.

"Legendary is one word for them," Jaehyun managed to say, his voice a little breathier than he intended. Up close, Leehan’s eyes were even more distracting. There was a soft focus in them, completely unbothered by the screaming toddler group three yards away.

Jaehyun glanced down at his confirmation paperwork, then back up, a slight frown of confusion breaking through his daze. "Wait...I’m sorry, I was under the impression that I would be meeting a 'Donghyun'? That was the name on the coordinator's email."

The guide let out another soft chuckle, his shoulders dropping in a relaxed, easy motion.

"Oh, that’s me," he murmured, leaning in just a fraction closer so his voice wouldn't carry over the kids' heads. A faint scent of sea-salt tracking and something clean, like cedar, drifted over. "Donghyun is my actual name. I just go by Leehan during the tours. It's a bit easier for the kids to remember, and honestly, it sounds a lot less intimidating when I'm trying to convince them that the giant spider crabs won't climb out of the glass to eat their shoelaces."

"Right," Jaehyun said, his brain stalling on the syllable. Donghyun. The name felt heavy and intimate in his mind, a sharp contrast to the bright, public persona of Leehan. "Leehan. Got it. Well, Dong—uh, Leehan. We're all yours."

"Excellent," Leehan said, straightening up and flashing that devastating crescent-moon smile once more. He reached into a small canvas pouch hooked to his belt. "First rule of the voyage: anyone who answers a trivia question correctly gets an official Explorer Badge ." He flashed a shiny, holographic sticker of an otter.

"I want the otter!" Minho yelled, immediately dropping his partner's hand.

"Hands back with your buddy, Minho," Jaehyun guided smoothly, his eyes never quite leaving Leehan's face.

"But Mr. Myungie," Minho complained, his bottom lip jutting out as he reluctantly grabbed Jihoon’s sleeve instead of his hand. "Jihoon’s hands are sticky from the bus juice, and I want to be first in line to see the sharks anyway."

"The sharks aren't going anywhere, Minho, I promise," Leehan countered smoothly. He dropped to one knee again, seamlessly sliding between the two boys. He pulled a small, sealed packet of wet wipes from his canvas hip pouch and handed it over to Jihoon with a conspiratorial wink. "Here, use a magic deep-sea towel. It cleans off bus juice instantly so the sharks don't mistake your fingers for little fish sticks."

Jihoon giggled, immediately ripping the packet open, while Minho’s eyes went wide at the mention of fish sticks.

Watching from above, Jaehyun felt his chest tighten in a way that had absolutely nothing to do with classroom management. The effortless patience, the quick humor—it was entirely unfair how attractive it was. He shifted his weight, using his clipboard to block his view of Leehan's face for just a second so he could try to reclaim his scattered focus.

Leehan stood back up, dusting off his knees, his gaze flicking back up to meet Jaehyun’s. Those stunning crescent-moon eyes crinkled at the corners. "All set, Mr. Myungie. Shall we begin the actual voyage?"

"Lead the way, Captain Hannie," Jaehyun said. His voice was a little softer than his usual authoritative teacher tone, a subtle slip that he hoped the noisy atrium echoes would swallow up.

"Are we ready to see the krill?" Leehan shouted to the rest of the class, pointing his flashlight toward the dark, glowing archway of the first exhibit.

"Yes, Captain Hannie!" 

As the kids surged forward into the dim tunnel, Leehan slowed his pace, deliberately falling into step right next to Jaehyun. Their shoulders brushed under the shifting blue lights—a brief, warm contact that made the skin on Jaehyun's arm prickle with heat.

"You're really good with them," Jaehyun murmured, tilting his head slightly toward Leehan. "Most people panic the second a seven-year-old mentions sticky hands or shark attacks."

Leehan let out a soft, humored breath, adjusting the strap of his canvas pouch. "Thanks. It kind of comes with the job description around here, but honestly? It’s just about speaking their language. If you tell them a shark will eat their shoelaces, they listen way better than if you give them a safety lecture."

Jaehyun smiled, the genuine ease in Leehan's voice making the knot of field-trip tension in his shoulders loosen just a fraction.

"Nice call-and-response back there on the plaza, by the way," Leehan noted casually, keeping his eyes on the bobbing backpacks ahead. "The 'everybody freeze' bit. Very effective."

"Thanks," Jaehyun said, steering his eyes strictly forward to hide the rapid, unmistakable creep of a blush warming his neck. He tightened his grip on his clipboard, trying to sound more like a seasoned educator and less like a man completely thrown off by a nice voice. "They’ve always got so much built-up energy, you know? If you don't give them a reason to actively use their bodies and move around, they’ll just invent their own ways to do it. It's easier to redirect the chaos before they start climbing the walls."

"Makes sense. Work with the current, not against it," Leehan murmured. The comment was light, but there was a quiet sincerity in his voice that made Jaehyun's heart do a dangerous, erratic flip. “I might have to steal that for when the high school tour groups get out of hand.”

Jaehyun bit the inside of his cheek, adjusting his grip on the clipboard yet again. "Feel free. Just don't let them see you sweat, otherwise, they smell the weakness."

Leehan laughed, a soft, genuine sound that vibrated right through the small space between them as they stepped deeper into the glowing blue darkness of the exhibits. "I'll keep that in mind."

"Look! It's glowing!"

Minho’s voice shattered the quiet bubble between them. He was currently pressed flat against the glass of the first major tank, his nose squished into a round button as he stared at a massive, swirling school of tiny bioluminescent krill. Jihoon was right beside him, completely forgetting his clean hands as he actively tapped on the acrylic pane.

"Jihoon, palms down, hands off the glass," Jaehyun said smoothly, his teacher voice taking over without a single beat of hesitation. "We watch with our eyes."

Jihoon immediately pulled his hands back, locking them safely behind his cardiganned back. "Sorry, Mr. Myungie."

"Thank you," Jaehyun smiled, giving the boy an encouraging nod before glancing at Leehan.

Leehan was already looking at him, an appreciative hummed approval quiet in his throat. He seamlessly picked up right where Jaehyun left off, addressing the boys with a warm smile. "Mr. Myungie is exactly right. Actually, did you guys know that if you tap too hard, the krill think a giant predator is coming? They get so scared they might accidentally flash all their lights at once and run out of battery."

Jihoon’s eyes went wide. "We definitely don't want them to run out of battery."

"Exactly," Leehan chuckled, giving the boys a collaborative nod before his eyes flicked back up to meet Jaehyun’s. The deep ocean lighting caught the sharp line of Leehan’s jaw, casting his crescent-moon eyes into a soft shadow that made them look incredibly focused. "Teamwork. We have to protect our underwater friends."

Jaehyun offered a small, breathless nod, completely helpless against the sudden, rapid skip of his pulse. "Right. No draining the batteries, boys."

"Come on, explorers," Leehan called out to the rest of the class, unhooking a small laser pointer from his belt to guide their eyes upward. "Follow me. Next up are the spotted eagle rays, and if we're lucky, one of them might wave at us."

As the second-graders eagerly shuffled forward in their pairs, Leehan waited back for a split second, casting one last lingering, amused glance at Jaehyun before leading the line. Jaehyun took a slow, grounding breath, tapping his pen against his clipboard to force his brain back into teacher-mode, and followed them into the deep.

By the time the class shuffled past the Amazonian rainforest exhibit, the morning’s polite curiosity had entirely dissolved into the pre-lunch jitters. Headcounts were getting harder as pairs drifted apart, and Jaehyun could practically hear the collective growl of twenty-four second-grade stomachs over the simulated sound of a tropical waterfall.

"Alright, explorers," Leehan called out, his voice a steady, calm anchor against the rising tide of antsy chatter. He held up a hand, clicking his pen to gather their straying eyes. "We are making a pitstop. Follow me this way to the Reef Room."

The "Reef Room" was clearly the aquarium’s designated birthday party hub, complete with a neon-painted coral mural on the back wall and a window that looked directly into a sleepy sea turtle enclosure. For today, however, the staff had pushed the brightly colored tables into long rows, transforming it into a makeshift cafeteria.

Within minutes, the room was a controlled explosion of rustling plastic baggies, snapping bento box lids, and the high-pitched bartering of fruit snacks for juice boxes.

Jaehyun collapsed onto one of the plastic chairs at a smaller, isolated round table near the back, letting out a long, pathetic breath that had his shoulders sinking a full two inches. He dropped his clipboard onto the table and rubbed the bridge of his nose.

"Rough leg of the tour?" a smooth voice asked.

Jaehyun looked up to find Leehan sliding into the chair across from him. The guide had unclipped his staff walkie-talkie, setting it neatly next to Jaehyun's clipboard, and was watching him with an amused, sympathetic tilt to his lips.

"I love them, I really do," Jaehyun murmured, unlatching his own massive, heavily insulated lunchbox. "But around hour four, the ratio of children to my remaining brain cells starts looking really grim."

Leehan laughed, a quiet, low sound that felt entirely too intimate for a room currently echoing with the screams of children debating whether sharks could eat a helicopter. "You're doing great, Mr. Myungie. Seriously. I've seen seasoned camp counselors throw in the towel by this point in the day."

"Jaehyun, please. That name is going to give me hives," Jaehyun joked, though a tiny, residual hint of warmth touched the tips of his ears at the reminder. He pulled out a neatly packed glass container of homemade kimbap, along with a small side of fresh fruit. "How long have you been doing this? You handle them like a pro."

"About two years," Leehan said, leaning back and resting his forearm over the edge of the table. "I started as a volunteer while I was finishing my degree. I mostly do the deep-sea research side of things now, but they pull me out for tour duty when the groups are...'legendary.'"

"Ah. So you drew the short straw today."

"I don't know," Leehan murmured, his crescent eyes locking onto Jaehyun's with that soft, entirely unbothered focus. "I think I got pretty lucky."

Jaehyun's hand paused over his container. He swallowed, suddenly very glad he hadn't taken a bite of food yet, because his throat had momentarily closed up. He forced a small laugh, gesturing vaguely around the noisy room. "If your definition of lucky is a room that smells like peanut butter and damp sneakers, then sure."

Leehan smiled, the expression easy and entirely genuine, before his eyes drifted toward the door where a few other staff members were passing by.

It was only then that Jaehyun realized Leehan’s hands were empty. There was no lunchbox, no staff cafeteria tray, not even a stray granola bar from his pockets.

"Wait," Jaehyun blinked, looking between Leehan and the empty table space in front of him. "Where's your lunch?"

Leehan blinked, looking slightly caught out before he waved a dismissive hand. "Oh, don't worry about me. My shift technically ends a bit later, so I usually just grab something from the cafe down the street once my tour group leaves."

Jaehyun frowned, his innate teacher-instincts immediately flaring up. "The cafe down the street is a fifteen-minute walk, and you've been on your feet talking since nine AM. You can't just skip lunch."

"I'm fine, really," Leehan insisted, a small, sheepish chuckle escaping him as he tried to downplay it. "I have a pretty high tolerance for fasting. Marine biology field hours train you for it."

"Absolutely not," Jaehyun said flatly, already sliding the lid off his kimbap container. He picked up the clean pair of wooden chopsticks he'd brought as backups and snapped them apart with a sharp crack, extending them toward Leehan. "Here. Eat."

Leehan stared at the chopsticks, then at the perfectly rolled, colorful kimbap. "No, Mr. Myung—Jaehyun, really, that's your lunch. I can't take your food."

"I packed way too much because I thought I'd be stress-eating," Jaehyun lied smoothly, pushing the glass container right into the center of the table between them. "And if you drop from low blood sugar halfway through the jellyfish exhibit, I'm the one who has to carry you out. Think of it as a safety measure for my afternoon."

Leehan looked at the kimbap, then up to Jaehyun, a soft, helpless sort of amusement taking over his face. "Is this how you get the second graders to eat their vegetables?"

"It's highly effective," Jaehyun said, tilting his head with a challenging smile. "Are you going to make me repeat myself, Captain?"

Leehan let out a quiet breath that sounded a lot like a surrender. He took the chopsticks from Jaehyun's hand, his fingers brushing against Jaehyun's palm for a brief, warm second. "Alright. Since it's a safety measure."

He picked up a piece, popping it into his mouth. Jaehyun watched him chew, suddenly feeling a completely different kind of antsy tension in his chest as he waited for a verdict.

Leehan’s eyes widened slightly, a genuine hum of appreciation vibrating in his throat. "Wow. Did you actually make this yourself?"

"My roommate helped roll them last night, but I did the prep," Jaehyun said, a small, proud smile breaking through his earlier exhaustion. He finally picked up his own fork to start on his fruit. "Good?"

"Incredible," Leehan said, already eyeing a second piece with significantly less hesitation than before. He looked across the table, his gaze lingering on Jaehyun's face as the rowdy noise of the Reef Room seemed to fade into a comfortable, easy background hum. "Thanks, Jaehyun. I owe you one."

"Just get us through the touch-tanks without anyone trying to pocket a starfish," Jaehyun replied, his heart doing another one of those dangerous, erratic flips, "and we'll call it even."

Leehan swallowed the second piece of kimbap, a soft, content expression settling into his features. He leaned his forearms back on the table, turning the chopsticks idly between his fingers. "I mean it, though. I think I can handle a few rogue starfish snatchers if it means getting a home-cooked meal out of it."

"Don't speak too soon," Jaehyun laughed, using his fork to stab a piece of melon. "You haven't seen them at the touch-tanks yet. Yesterday we did a preview lesson on marine life, and Hajun spent twenty minutes asking if a stingray would let him ride it like a skateboard. I'm on high alert."

Leehan’s eyes crinkled into those familiar, amused crescents. "Well, for the record, the stingrays are very accommodating, but they do have a strict no-skateboarding policy. I'll make sure to reinforce that during the safety briefing." He paused, his gaze drifting over to the chaotic rows of low tables where Yuna was currently trying to trade a string cheese for an entire bag of chips. "They seem like good kids, though. Energetic, but they really listen to you."

He turned back around, propping his chin in his hand, looking genuinely curious. "How long have you been doing this, anyway? Teaching second grade feels like a specific kind of mental extreme sports."

"It's my third year with this age group, fourth year teaching overall," Jaehyun said, a small smile tugging at his lips as he glanced over his shoulder at the kids. "And yeah, it definitely requires a lot of cardio. But I actually started out tutoring high schoolers when I was in college. I thought I wanted to teach AP History."

"High school history to second-grade touch-tanks is a bit of a leap," Leehan noted, shifting slightly closer over the narrow table. "What happened?"

"I realized teenagers are way too cool to care about my fun facts," Jaehyun admitted, groaning softly as he rubbed the back of his neck. "But seven-year-olds? If you tell them a castle used to have a moat filled with alligators, they look at you like you're a wizard. They still have all that unfiltered curiosity. It’s exhausting, but...I don't know. When you see the look on their faces when they finally get a concept, or when they get genuinely excited about a sea turtle? It makes the chaos worth it."

He looked back to find Leehan watching him with a remarkably soft, attentive focus. There was no teasing spark in the guide's eyes this time—just a quiet, steady kind of admiration that made Jaehyun’s chest feel suddenly light and crowded all at once.

"What?" Jaehyun asked, a little self-consciously, his fingers tightening slightly around his fork.

"Nothing," Leehan murmured, a slow, gentle smile touching his lips. "Just...it's easy to see why they like you so much. You really care about them."

A sudden, faint flush crept right back up to the tips of Jaehyun’s ears. He quickly pushed the glass container forward to give himself something to do, clearing his throat. "Well, uh. Someone has to keep them from climbing into the exhibits. Which means you should finish the rest of this kimbap. Seriously. Consider it fueling up for the touch-tank battle."

Leehan held up his hands in a defensive gesture, laughing softly as he shook his head. "Oh, no. I couldn't. I've already cleared out half your lunch box, and I have a reputation as a professional guide to uphold. I can’t be caught entirely comatose from a food coma right before the penguin presentation."

"Are you slandering my kimbap recipe right now?" Jaehyun asked, a playful, challenging glint returning to his eyes as he leaned forward just a fraction. "Because I'm pretty sure that's a punishable offense in at least three different oceans."

"I would never slander the kimbap," Leehan defended smoothly, pointing a chopstick at him with a mock-serious expression. "It’s dangerously good. That’s the problem. If I eat two more pieces, I’m going to start explaining the benthic ecosystem in a whisper so I don't wake myself up."

"Alright, alright, I'll spare you the food coma," Jaehyun joked, his heart doing another one of those dangerous, erratic little flips at how easily the banter flowed between them. He capped the container and slipped it back into his bag, the lingering warmth of the conversation settling comfortably between them as the lunch hour began to wind down.

"Cap-tain Han-nie! Cap-tain Han-nie!"

The chant started with Minho but spread like wildfire through the line as the second-graders marched into the Touch Tank Pavilion. The room was bright, filled with the gentle, rhythmic hum of water filters and the refreshing scent of heavily salted water. Low, shallow rock pools stretched across the room, designed perfectly at a seven-year-old’s chest height.

Leehan stepped up to the edge of the central pool, turning around to face the kids with a bright smile. He raised his hands, and the chanting died down to an excited, vibrating murmur.

"Alright, explorers, welcome to the shallow seas," Leehan said, his voice dropping into that warm, captivating storyteller cadence. "Before we touch anything, we need to learn the golden rule of the touch tanks. Hands out, index fingers only." He held up his own index finger. "We use two gentle fingers, like a soft feather brushing against the water. No grabbing, no lifting, and absolutely no tickling. Deal?"

"Deal!" twenty-four voices shouted back.

"Excellent. Now, who can tell me what this is?" Leehan pointed into the clear, shallow water where a dark, bumpy creature was slowly lumbering over a rock.

A boy named Daeshik eagerly raised his hand, nearly jumping out of his sneakers. "It's a sea cucumber! My dad said they look like poop!"

The entire class dissolved into a fit of giggles. Jaehyun hid a grin behind his clipboard, stepping closer to see how Leehan would handle it.

Leehan didn't even blink. He let out a soft laugh, dropping down to his knees at the edge of the tank so he was right there with them. "Your dad isn't entirely wrong, Daeshik! They do look a bit funny. But did you know that sea cucumbers are actually the vacuum cleaners of the ocean? They crawl along the sandy bottom, eat all the dead stuff and sand, clean it inside their bodies, and poop out clean, fresh sand. Without them, the ocean floor would be super dirty."

Daeshik’s eyes went completely round. "They're vacuum cleaners?"

"Exactly," Leehan smiled, guiding Daeshik’s hand forward. "Go ahead. Two fingers, very gently on its back."

Daeshik braced himself, pressing his fingers to the creature. "Whoa...it feels like a squishy pickle!"

As the rest of the kids eagerly crowded around the edges of the pool, plunging their arms in up to their elbows, the questions started flying like rapid-fire. Leehan moved between them like a natural, never once rushing an answer, his eyes sparkling with a deep, genuine passion for every single creature.

"Captain Hannie! Why is this starfish so hard?" asked a quiet girl named Hana, gently touching a bright blue sea star. "I thought they were squishy like jelly."

"Ah, that's a blue Linckia sea star," Leehan explained softly, leaning over the glass next to her. "They actually have an skeleton made of tiny bones right under their skin, almost like armor. It protects them from hungry fish. But if you look really closely at the bottom—see those tiny, moving clear things? Those are its tube feet. It uses water power to pump them up and walk around."

"It's walking on my finger!" Hana gasped, a massive, delighted smile breaking across her face.

Jaehyun watched the interaction from just a few feet away, completely mesmerized. It was one thing to see a guide rattle off facts from a manual, but Leehan spoke about the marine life as if they were his personal friends. He knew every scientific name, every strange defense mechanism, and he translated it into second-grade logic effortlessly.

"Mr. Myungie! Look! I found a baby shark!"

Jaehyun’s teacher-instincts flared instantly at the word shark, and he hurried over to the corner of the tank where Minho and a few other boys were huddled.

Right there, tucked into a rocky crevice beneath the shallow water, was a small, mottled brown shark, barely two feet long, resting completely still. Minho was already hovering his hand over the water, his eyes wide with a mix of terror and absolute excitement.

"Minho, wait," Jaehyun said quickly, reaching out to gently catch the boy's shoulder. "Let's ask Captain Hannie first if that one is okay to touch."

Leehan was already sliding in right beside them, his presence instantly calming the sudden spike of tension. He looked down into the water, his expression softening.

"It's okay, Mr. Myungie," Leehan murmured, casting a warm, reassuring glance up at Jaehyun before looking back at the boys. "This is a banded bamboo shark. They’re very friendly, but they’re nocturnal, which means they sleep during the day. See how he’s just resting on the sand?"

"Is he having a nightmare?" Jihoon asked, peering closely at the shark's gills pumping slowly.

"No, he's just breathing," Leehan chuckled softly, the sound low and comforting. "But since he's sleeping, we have to be extra respectful. Minho, do you want to feel what a shark's skin feels like? Very gently, just on his back, away from his face."

Minho swallowed hard, nodding aggressively. He lowered his hand, his index finger making light contact with the shark's skin. He blinked, looking confused. "Wait. It feels like sandpaper. I thought it would be slimy."

"That’s because sharks don't have regular scales," Leehan explained, his voice rich with enthusiasm as he leaned his forearms against the ledge of the tank, completely unbothered by the water splashing onto his polo. "They have tiny, microscopic teeth all over their skin called dermal denticles. It helps them swim super fast through the water without making any noise, like an underwater superhero cape."

"An underwater superhero," Minho whispered, completely enchanted. He pulled his hand back, looking at his fingers as if he’d just touched magic. "I'm never washing this hand again."

"Please wash your hand before we get to the bus, Minho," Jaehyun chimed in, a breathless laugh escaping him.

Leehan stood up, brushing a stray drop of saltwater from his cheek, his gaze flicking directly to Jaehyun. The bright overhead lights of the pavilion caught the damp, dark strands of his hair, and up close, Jaehyun could see the faint outline of a few more custom fish pins he hadn't noticed earlier.

"You're incredible at this," Jaehyun said softly, stepping closer so his voice was just between the two of them over the ambient splashing of the pavilion. "Seriously. I think you just created five future marine biologists in the span of ten minutes."

Leehan’s crescent-moon eyes crinkled at the corners, a faint, handsome flush warming his cheeks. He rubbed the back of his neck, looking uncharacteristically shy for a moment. "Thanks. I just...I really love this stuff. When I was their age, someone took me to a tide pool and explained how hermit crabs pick out their shells, and I was hooked for life. I guess I just want to pass that on."

He paused, his gaze lingering on Jaehyun’s face, his eyes shifting from the energetic crowd of kids to focus entirely on the teacher. "Plus, it helps when their leader is keeping them from falling face-first into the stingray pool."

Jaehyun smiled, feeling that familiar, dangerous flutter kicking up in his chest again. "Hey, it's a team effort. Captain and co-captain."

"Co-captain," Leehan repeated, the word sliding out in a soft, low murmur that made Jaehyun's pulse jump. He tilted his head, a playful spark returning to his eyes. "I think that deserves an official promotion."

Before Jaehyun could ask what he meant, Leehan reached into his canvas hip pouch. His fingers brushed lightly against Jaehyun’s wrist as he stepped in close, reaching up to press something smooth and holographic directly onto the top corner of Jaehyun's plastic clipboard.

Jaehyun looked down. It was a shiny, glittering holographic sticker of a sea turtle wearing a tiny crown.

"The Explorer King badge," Leehan whispered, leaning in just enough that the clean, cedar-and-sea-salt scent enveloped Jaehyun entirely. "Only awarded to the most exceptional co-captains."

Jaehyun’s breath caught in his throat. He looked from the sticker back up to Leehan’s devastating, crescent-moon smile, his knuckles turning white around the edges of his clipboard as he tried to find his voice.

"Mr. Myungie! Hajun is trying to see if the hermit crab will bite his nose!"

The loud, panicked shout from across the pavilion shattered the moment. Jaehyun snapped his head toward the commotion, his teacher-brain instantly jolting back online.

"Hajun, get your nose out of the tank!" Jaehyun called out smoothly, though his voice was a little higher than usual. He turned back to Leehan, a helpless, flushed smile on his face. "Duty calls."

Leehan let out a rich, genuine laugh, gesturing toward the chaos. "Lead the way, co-captain. I've got your back."

The transition from the bright, splashing Touch Tank Pavilion to the Abyss Zone was like stepping into a different dimension. The walls faded into pitch-black, and the only illumination came from the eerie, glowing blue and violet lights of the deep-sea tanks. The ambient sound shifted from rushing water to a low, atmospheric hum that instantly quieted the kids down into a cautious, wide-eyed huddle.

"Stay close to your buddies," Jaehyun called out, his voice naturally dropping an octave to match the heavy stillness of the room.

He felt a sudden, sharp tug on his jacket hem. Looking down, he saw Hana standing frozen, her small fingers clutching his fabric so tightly her knuckles were white. Her big eyes were darting anxiously around the pitch-black walls, her lower lip trembling slightly under the glow of the violet blacklights.

Jaehyun didn't hesitate. He immediately dropped down into a crouch right in front of her, breaking his own line-of-sight with the rest of the class to focus entirely on her. He gently placed a hand on her shoulder, giving it a reassuring, grounding squeeze.

"Hey," Jaehyun murmured, his voice incredibly soft and warm. "It's just the deep ocean, Hana. No monsters, I promise."

Hana swallowed hard, her voice barely a whisper as she leaned closer to him. "But Mr. Myungie...it’s so dark. What if something jumps out of the water? What if the lights go all the way out?"

"If the lights go all the way out, I have a giant flashlight right here in my bag, and I'll turn it on instantly," Jaehyun promised, offering her a calm, steady smile. He reached over and gently loosened her rigid grip on his jacket, switching it so her small hand was securely holding onto his wrist instead. "And nothing can jump out, because the glass is super thick to keep the water safe inside. Tell you what—you can hold onto my arm for this whole exhibit, okay? We’ll be teammates."

Hana looked at his hand, then up at his gentle face, and gave a small, relieved nod, her shoulders visibly relaxing.

"Mr. Myungie is exactly right, Hana," Leehan’s voice drifted over from the front of the line. It was smooth, quiet, and remarkably grounding in the dark. He unhooked a small, low-intensity red flashlight from his belt, pointing it safely down at the floor to illuminate a clear, warm path for their sneakers.

Leehan offered Hana a gentle, understanding smile, his eyes softening as he addressed the whole worried group. "The deep sea can look a little spooky at first because we aren't used to the dark, but there's nothing scary here. The animals down here are actually very quiet, gentle creatures who are just minding their own business. They’re just like us—they like the dark because it helps them rest and stay safe."

Jaehyun looked up from his crouch, watching Leehan in the dim light. The way the guide had immediately stepped in to back him up, changing his tone entirely to make sure Hana felt safe, sent a quiet, distinct thrum right through Jaehyun's chest. It wasn't just professional; it was genuinely kind.

"See?" Jaehyun whispered down to Hana, standing back up to his full height but keeping his wrist right where she could hold it. "Captain Hannie knows the ocean inside out. We're totally safe."

Hana gave a tiny, much braver nod, her eyes turning toward the central tank where a cluster of pale creatures were crawling slowly over a heap of artificial rock.

Leehan didn't move immediately. He remained standing a few feet away, his flashlight still pointed safely at the ground, but his gaze was locked onto Jaehyun. In the dim, violet glow of the Abyss Zone, his crescent-moon eyes weren't crinkling with his usual energetic "tour-guide" smile. Instead, they were wide and remarkably soft, taking in the way Jaehyun casually adjusted his stance so Hana could stay anchored to his arm, his other hand already smoothing down the edge of Minho's peeling name tag without a second thought.

There was a quiet, lingering beat where Leehan just watched him, a look of genuine, struck admiration softening his features, before he caught himself and seamlessly picked up the thread.

"Whoa," Minho breathed, his nose instantly pressing against the acrylic of the main display. "They look like giant, armored roaches. Are they alien bugs?"

"They’re giant isopods, Minho," Leehan explained, stepping closer to the tank but keeping his voice in that lower, soothing cadence he’d used for Hana. He dropped down to the kids' eye level. "They live thousands of meters below the surface where it’s freezing cold. Because there’s not a lot of food down there, they have to be incredibly patient. Sometimes they go months without eating a single thing, just waiting quietly."

"Months?" Jihoon gasped, his hand flying to his mouth. "I get mad if my mom is five minutes late with my afternoon snack."

Leehan let out a soft, genuine chuckle, standing back up to his full height. "Me too, Jihoon. That's why I think they're pretty impressive."

Feeling a fresh burst of bravery from Leehan's reassurance, Hana finally let go of Jaehyun’s wrist. She gave his sleeve one last grateful pat before bouncing on her heels over to her best friend, Yoonah, eagerly pointing at the pale, sprawling creatures behind the glass.

Jaehyun smiled warmly as he watched her join the huddle, his chest loosening now that she was comfortable. But as he stepped back to give the growing crowd of kids more room around the display, the narrow walkway suddenly grew congested. A rowdy family group came pushing past from the opposite direction, forcing Jaehyun to take a hasty step backward to avoid a stray stroller.

Before his heel could catch on the edge of the display base, a firm, warm hand pressed directly against the small of his back, steadying him instantly.

Jaehyun froze. Even through the fabric of his shirt, the heat of Leehan’s palm was unmistakable.

"Watch your step," Leehan murmured. Because of the crowded walkway, he didn't immediately pull his hand away. He stayed right there, his chest barely an inch from Jaehyun’s shoulder, his physical presence acting as a quiet shield between Jaehyun and the passing crowd.

"Thanks," Jaehyun managed to say, his breath catching in his throat. He looked up, his eyes colliding with Leehan's in the dim, violet glow.

Up close, the public "Captain Hannie" persona felt completely absent. Leehan was looking down at him with a remarkably steady, focused intensity—the kind of look that made the ambient chatter of twenty-four second-graders completely fade into white noise.

"You're really good at that," Leehan said softly. The comment was quiet, meant strictly for Jaehyun's ears over the low hum of the filtration systems.

Jaehyun blinked, his heart doing a sudden, dangerous vertical leap against his ribs. "At...keeping them from falling into the glass?"

"At making them feel safe," Leehan corrected. A tiny, slow smile touched the corner of his lips, his thumb shifting just a fraction against Jaehyun's back before he finally, reluctantly let his hand drop. "Hana was pretty spooked. Most teachers just tell them to keep moving, but you...you really look out for them."

A sudden, fierce spike of heat bloomed along the tips of Jaehyun's ears, completely unbothered by the air-conditioned chill of the Abyss Room. He tightened his grip on his clipboard, desperately trying to steady his voice. "Oh. Well. They're...they're worth looking out for."

"Captain Hannie!" Yuna’s voice cut through the dark, her neon-pink nametag glowing faintly under the blacklights. She was pointing at a smaller tank nearby. "Why does this fish have a fishing pole attached to its forehead? Is it going to catch its own dinner?"

Leehan’s gaze lingered on Jaehyun for just one more half-second—an implicit, heavy beat where his eyes dropped slightly before rising back up to meet Jaehyun's—before he turned his attention back to the class.

"That's a football anglerfish, Yuna," Leehan said, stepping over to her tank, though his shoulder still lightly brushed against Jaehyun’s as he moved into the space. "And you are exactly right. That little pole glows in the dark to help it find friends in the deep ocean..."

As Leehan continued the lesson, his voice rich and engaging, Jaehyun took a slow, grounding breath. Hana was still securely holding onto his wrist, completely relaxed now, but Jaehyun’s own pulse was currently attempting a solo sprint.

He looked over at Leehan, who was laughing softly at something Daeshik said. For the first time all day, Jaehyun realized the subtle shift. It wasn't just that the guide was breathtakingly handsome or good at his job. It was the fact that behind the polished corporate polo and the sea-foam lanyard, Leehan was actively paying attention to him, too.

By the time the KOZ Elementary class finally shuffled out of the cool, dim sanctuary of the aquarium, the afternoon sun hit them like a wall of physical heat. The yellow school bus was already idling by the concrete plaza curb, its air conditioning humming loudly.

"Alright, explorers, huddle up one last time!" Leehan called out, his voice crisp and cheerful despite having spent the last five hours answering questions about whale sharks and sea cucumber poop.

"Noooo!" Minho groaned dramatically, letting his entire body go limp as he clung to a metal stanchion near the exit doors. "We can't leave yet! We didn't even get to see the penguins do a belly slide!"

"Yeah! And I wanted to ask Captain Hannie if the giant octopus can play video games with eight controllers!" Daeshik chimed in, crossing his arms and planting his sneakers firmly onto the concrete plaza. "Can't we just stay for dinner? We can get food from the vending machines!"

"The machines require money, Daeshik, and the sharks have a very strict bedtime," Jaehyun called out, his voice a mix of exhausted amusement as he gently nudged the boy forward. "Line up, please. Your yellow submarine is waiting."

"But Mr. Myungie," Yuna whined, her lower lip jutting out as she tugged on her clownfish dress. "If we go back to school, we have to do math tomorrow. Can't Captain Hannie just be our teacher now?"

Leehan let out a soft, genuine laugh, dropping smoothly onto his knees on the concrete to bring himself down to their eye level. He opened his familiar canvas hip pouch, instantly drawing all twenty-four kids into a tight, captivated circle around him.

"Hey, a true captain always leaves a little bit of the ocean unexplored so you have a reason to come back," Leehan reassured them, his eyes crinkling into those familiar, warm crescents. "But to prove you all survived the voyage…everyone gets an official Deep-Sea Explorer Badge."

He pulled out a thick roll of glittering, holographic stickers, and the impending mutiny vanished into thin air, instantly replaced by pure sticker-induced chaos.

"I got the hammerhead shark! Mine is the strongest!" Minho yelled, proudly slapping the sticker right in the center of his forehead.

"Captain Hannie said hammerheads are slow," Jihoon countered, aggressively waving his own holographic manta ray in Minho’s face. "Mine can fly underwater. Captain Hannie, tell him mine is better!"

"They're both excellent specialized predators," Leehan laughed, holding up his hands to play referee as Yuna and Eunji began debating whether a neon jellyfish sticker was cooler than a blue tang. "No fighting on the plaza, explorers. Every badge has its own superpower."

Jaehyun watched the spectacle from a few feet away, leaning heavily against the metal handrail of the bus steps. His hair was slightly disheveled, his glasses falling down his nose, and his plastic clipboard felt like it weighed fifty pounds, but a warm, helpless smile was plastered across his face anyway. He looked down at the top corner of his board, where the little crowned sea turtle sticker from earlier was still shining brightly in the direct sunlight.

"Mr. Myungie! Minho is trying to put his shark sticker on a pigeon!"

Jaehyun let out a long, exhausted breath that sounded like a deflating tire. "Minho, leave the wildlife alone and get on the bus. Jihoon, backpack on both shoulders. Let’s go, kids."

It took a solid ten minutes of strategic herding, but eventually, all twenty-four second-graders were successfully pushed up the steps. The bus windows immediately filled with the muffled, high-pitched chaos of children fighting over window seats, leaving the plaza suddenly, beautifully quiet.

Jaehyun stayed on the bottom step, running a hand through his hair and using the edge of his sleeve to push his glasses back up the bridge of his nose. He let out one final, heavy sigh of relief, watching the bus doors hover open.

"Survival rate: one hundred percent," a smooth voice murmured.

Jaehyun looked up to find Leehan stepping out from beneath the shade of the plaza awning. Without the crowd of kids circling his knees, his posture looked remarkably relaxed, his hands tucked loosely into his pockets as he stopped at the base of the bus steps. Up close in the bright afternoon sun, his dark hair caught a soft sheen, and his sea-foam lanyard clinked quietly against his custom beluga badge holder.

"You look like you just wrestled a giant squid," Leehan chuckled softly, his crescent-moon eyes crinkling at the corners with that same steady, focused warmth from the Deep Sea exhibit.

"Worse," Jaehyun corrected, a breathless, genuine laugh escaping him as he tapped his pen against his clipboard. "Second graders with holographic stickers. But thank you, Leehan. Seriously. I usually have to spend half these trips playing security guard, but they were so locked into everything you were saying. Even Hana forgot to be scared by the end of it."

"They're great kids. It's easy to be enthusiastic when the group leader actually cares," Leehan said easily. He leaned his shoulder against the side of the bus frame, looking up at Jaehyun with a casual, easy posture. He reached into his navy polo pocket, pulling out a standard, crisp white aquarium business card.

Instead of just handing it over, he turned it over in his fingers, uncapping a black marker he’d been holding in his palm with a sharp, clean click.

Before Jaehyun could process the movement, Leehan stepped up onto the very first bus stair. The sudden shift in height brought them completely eye-to-eye for a fraction of a second before Leehan leaned in, his shoulder brushing right against Jaehyun’s chest as he reached over the top of the plastic clipboard.

"The aquarium does an after-hours night tour on alternating Fridays," Leehan said, his voice dropping into a quiet, casual cadence, vibrating right next to Jaehyun's ear over the loud, rumbling hum of the bus engine. "The public groups leave by seven. There are no nametags, no sticky hands, and...it's a lot quieter."

Jaehyun’s brain stalled completely. Leehan was close—entirely too close. He had one hand steadying the edge of Jaehyun's clipboard while the other scrawled something against the plastic surface, his face mere inches from Jaehyun's neck.

With Leehan bent over the board, Jaehyun’s gaze was trapped. He couldn't look up without brushing noses, so his eyes dropped, landing squarely on Leehan’s arm.

Jaehyun watched, completely paralyzed, as the muscles in Leehan's forearm shifted smoothly beneath his skin, the tendons tightening with every stroke of the marker. As he pressed down to write the final digits, the hem of the navy polo sleeve tightened firmly around his bicep, the muscle flexing and rippling under the bright afternoon sun—smooth and surprisingly defined for a guy who spent his days talking to jellyfish. A faint scent of clean cedar and sea salt drifted off him, enveloping Jaehyun entirely.

Jaehyun swallowed hard, his own knuckles turning white where he held the other side of the clipboard. He prayed to whatever cosmic force was listening that Leehan couldn't hear the frantic, erratic solo sprint his heart was currently attempting.

Leehan capped the marker with his thumb, the sound snapping Jaehyun right out of his daze. He smoothly slid the card under the metal clip, right next to the crowned turtle, before stepping back down onto the concrete plaza.

Jaehyun looked down at the card. Scrawled across the back in neat, compact handwriting was a personal phone number, right beneath the words ‘Friday night?’

He forced his voice to stay level, a playful, slightly breathless smile pulling at the corner of his lips as he tried to blink away the image of Leehan’s flexed arm. "Is that an official scientific recommendation, Captain?"

"Just a personal one," Leehan chuckled softly, keeping his eyes locked onto Jaehyun's as his hands slid back into his pockets. He offered a lazy, cheerful wave. "You should come back and actually look at the fish sometime, Jaehyun. Without the entourage."

"I'll...definitely look over the schedule," Jaehyun managed to say, his ears burning a vivid, unmistakable pink as he backed up into the bus aisle.

"I'll hold you to it," Leehan smiled.

The bus doors folded shut with a heavy hiss of air, and the vehicle shifted into gear, pulling away from the curb. Jaehyun collapsed into the front-row seat, immediately pulling the small white card out from under the clip.

Through the tinted glass, he watched Leehan stand on the plaza, waving as twenty-four second-graders pressed their noses against the windows to scream their final, rowdy goodbyes to Captain Hannie. Jaehyun flipped the card over in his hands, running his thumb over the scrawled black ink of the number, entirely helpless against the ridiculous, simmering warmth blooming in his chest.

He looked down at his clipboard, tracing the edge of the glittering holographic turtle.

Friday, he thought, a wide, unstoppable smile breaking across his face as the bus hit the highway. Yeah. Friday definitely works.