Secrets in the Temporary Lab

A little before the start of first period in Demon Exchange class. Seoyeun's temporary research lab. It was a narrow room. One desk, two chairs, shelves stacked with documents. There was only one window, and the blinds were drawn.

Seoyeun set down her coffee and lightly snapped her fingers.

Pop.

A small summoning circle unfolded in midair, and a white butterfly appeared. Rainbow-colored powder scattered from its wings. The butterfly sprinkled the powder here and there as it scanned the walls and ceiling. It was a summoned beast specialized in detecting eavesdropping spells.

Window cracks, behind the drawers, ceiling corners. After checking every nook and cranny, the butterfly returned to perch on Seoyeun's shoulder.

Flutter.

It folded its wings. All clear.

"……."

Seoyeun left the butterfly summoned for a bit longer. She planned to keep it up until the conversation ended. After the Woohyunho incident, she had no choice but to be even more cautious. If even the inspector sent by the Management Bureau was a demon, what could she trust…?

Then.

Knock knock.

"Come in."

The door opened. In walked Seha, wearing his uniform with his bag slung over his shoulder. Ruby ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠was cradled in his arms. Spotting Seoyeun, Ruby waved its front paw in greeting. The pink paw pads briefly stole her attention.

Seha's gaze lingered on Seoyeun's butterfly for a moment.

"Pretty summoned beast."

"Sit."

Seoyeun pointed to the empty chair. Seha sat in the round one. Ruby hopped down onto his lap. Its eyes were fixed on Seoyeun's butterfly. Its tail swished left and right. Hunting instinct or curiosity?

Seoyeun glanced at Ruby and said, "Don't catch it."

"Nyaaong."

Ruby turned its head away, pretending innocence. But its tail kept wagging.

Seoyeun opened her mouth.

"I called you to talk about yesterday."

Yesterday's events. The upper demon that had infiltrated the academy in human guise. And the training ground half-destroyed.

"First off, the training ground's been written off as a facility accident. Malfunction in the mana-blocking spell."

Seha nodded. "Yes."

Seoyeun emphasized firmly, "Don't tell anyone about yesterday. Not the professors, not your friends."

"Got it."

Seoyeun seemed relieved and turned her head. "And about the Woohyunho case—"

"Teacher."

Seha cut her off. Seoyeun looked back at him.

"Can I ask one thing?"

"……What?"

Seha stared straight at Seoyeun. "You're an investigator, right?"

"……."

The butterfly on her shoulder fluttered its wings once.

"That demon yesterday said it."

Seha spoke slowly. "'No evidence left, so that lady investigator can't do a thing.'"

"……."

"Lady investigator."

Seha looked at Seoyeun. "You can summon a unicorn."

His eyes were filled with certainty.

"Someone who handles unicorn-class divine beasts doing temp teacher duty? It's been weird from the start. With that skill level, you should be out in the field. Even for Class A."

Seoyeun said nothing.

"You showed up right after Dahong was summoned."

"……."

"So you're not really a teacher—you're an investigator. Here to look into something. Probably related to Dahong."

The lab fell silent. The butterfly's wings trembled faintly.

Seoyeun stared at Seha wordlessly. The timid boy's eyes seemed like those of someone else overnight.

Seoyeun let out a small sigh. "You're right."

She admitted it. "I'm a Management Bureau investigator. The temp teacher gig is cover."

Seha's expression didn't change. He'd already figured it out. Instead, he clenched his fist slightly on his lap.

"Did Dahong… do something?"

Seoyeun took a sip of coffee. "…Right after Dahong was summoned, a few incidents happened. I'm here because she might be connected."

She avoided the word murder. No need to make him shoulder unnecessary blame.

Seha sensed she didn't want to elaborate and didn't press. Instead, he asked something else. "So Woohyunho was part of your investigation too?"

"Auditor. Upper brass sent him because my reports were 'inadequate.'"

"And that auditor was a demon."

"……Yeah."

"If someone from the Management Bureau was a demon, doesn't that mean there's a problem in the Bureau itself?"

Seoyeun laughed self-deprecatingly. "Exactly. The Bureau's in ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠chaos right now. Their own auditor was an upper demon's host."

"Then…."

"Internal investigation's underway. External probes on the academy are on hold for a while."

"Including on Dahong?"

"For the time being."

Seha's shoulders relaxed ever so slightly. Seoyeun didn't miss it.

"Seha."

"Yes."

"Honestly surprised you pieced it together."

"……."

"But there are things it's better you don't know. Try to understand."

Seha nodded. "Yes."

"That's all for today. Go get ready for class."

"Thank you."

Scrape.

Seha stood. As he turned, Seoyeun swiveled her chair toward the desk. Ruby gave one last paw-wave at the butterfly. Seha stroked Ruby as he headed out.

Click.

The door shut. Seoyeun stared at the empty chair. The butterfly on her shoulder quietly folded its wings.

She didn't ask.

What Dahong was.

Doesn't care what, or plans to figure it out himself…?

She took a sip of coffee. It was lukewarm.

Leaving Seoyeun's lab, Seha headed to the classroom. Ruby yawned hugely in his arms.

"Ruby, sleepy?"

"Nyaa."

Not really, apparently. He walked the hallway. Morning sunlight streamed through the windows. Students were arriving through the school gate. Yesterday's battle with the upper demon felt like a lie.

He reached the classroom door. Laughter came from inside.

Scrape.

He opened it. Dahong leaned against the desk next to his seat. Isol, Harin, and Jinho surrounded her. Isol was excitedly talking about something. Harin stood with arms crossed, listening. Jinho nodded beside her. Dahong listened to Isol with a faint smile.

"Ah, Seha!"

Isol spotted him and waved. "Where were you? Dahong unnie got here first."

"Oh, the teacher wanted to see me for a sec…."

"Yu Seha."

Harin approached. "What were you doing at the training ground yesterday?"

"……?"

Seha shut his mouth. How did Harin know he'd gone to the training ground? Did Dahong say something? He glanced at her, but Dahong just blinked impassively.

"Heard a massive boom from the training grounds yesterday afternoon. Like an explosion."

"……."

"Checked this morning—Training Ground 3's closed. You were the one who used it after school yesterday."

Harin stated flatly. Cold sweat beaded on Seha's brow. She'd checked the terminal logs, apparently. A blind spot he hadn't considered.

"Ah, uh, well… I was experimenting with spells and it kinda malfunctioned…."

"Malfunction bad enough to shut down a training ground?"

Harin tilted her head. She seemed purely curious. Seha sweated internally, desperately crafting an excuse.

"Haha, I was practicing resummoning, but something went wrong and boom—big explosion…. And the mana-block spell failed too. Blasted the floor. That's why I was just coming from the office…."

"…Hmm, okay?"

Harin didn't pry further. Lucky she didn't know much about summoning.

Jinho patted Seha's shoulder. "Rough one, huh."

"……Yeah."

Seha sighed inwardly in relief and sat at his desk, hanging his bag on the side. Then Isol clapped.

"Oh, right! Gotta tell Seha too."

"……Huh? Tell me what?"

Seha tilted his head.

"My unnie's party just got promoted. Average combat power to E-rank."

"Oh, really?"

"Unnie was the only E before, rest F, so average F+. But everyone else leveled up!"

"Impressive."

"Right?"

Isol grinned. "So, they're challenging a D-rank gate this time."

"D-rank?"

Seha blinked. An E-rank party tackling a D-gate? Even with experience, wasn't that pushing it?

Reading his face, Isol waved. "That's why! Unnie invited us along."

"Us?"

"Yeah. Our group one. You, me, Harin, Jinho."

Isol pointed at Dahong. "Dahong unnie too."

"……."

"Her party's a bit short on raw power ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠but loaded with field experience. Gates every day. We're the opposite?"

Isol counted on her fingers. "We got combat power but zero real fights."

"……True."

"Perfect combo! They lead with experience, we push with strength."

Not a bad setup. Academy freshmen averaged D-rank power. Class A was a notch up, C-rank. Group one's average C- to C. Combined with Jisoo's E-rank party, a D-gate was doable.

"Told Dahong unnie earlier—she's in!"

"……."

Seha shot Dahong a glare. She gazed out the window. Perfect poker face.

"Dahong."

"Yeah."

"Not even a word to me?"

"You weren't here."

"Then wait till I got back!"

"Isol asked, I answered."

"That's basically deciding!"

"You against?"

"It's not that, it's the order—!"

"Then we're good."

Seha's mouth worked soundlessly. Everything decided without him.

"……Sigh."

He exhaled. But overall, not bad. D-rank gate. Real combat. Not classroom theory or training dummies—this was the real deal.

Yesterday, he'd vowed it. To get stronger. Not get fooled next time. Not just hide behind Dahong.

This could be the first step.

"…Okay. Let's go."

Seha agreed.

"Yay!"

Isol beamed. Ding dong dang—.

First period bell rang. Friends returned to seats. Ruby hopped onto the desk, sprawling in the sunbeam to loaf.

Seha sidestepped to avoid blocking ‍‍‌‌⁠​​⁠‌​​‍​​‍​‌​⁠‍‌‍⁠⁠‌⁠‌‍‌‍‌‌‌‍⁠​‌​‌​‌‍‌‌‌⁠‍​​‌‍⁠‌‌⁠⁠it and pulled out his textbook. The weekend was already looking fun.