He was avoiding me. 

 He hadn’t scheduled another tutoring session since the last one; he actively avoided my gaze in class and the hallways, suddenly finding urgent business in the staff room whenever I approached him. So, I began to act good. I completed my assignments, getting most of them intentionally wrong, playing the part of the struggling but trying student. 

 I had spooked him. I had pushed too hard, so now I had to ease back and make him feel in control again. 

Slow and steady. I cautioned myself. 

I couldn’t catch him in the act if he was constantly avoiding me. Showing some effort would encourage him, maybe win some sympathy for him, and let him drop his guard again.

Three weeks after he'd punished me with Trash Duty, I got my breakthrough.

The late afternoon sun baked the rural high school, thickening the summer air with humidity. Cicadas hummed relentlessly outside the open windows, their shrill chorus mixing with the strained drone of the air conditioner and the rhythmic click of oscillating ceiling fans that did little to cut the heat.

A few students had warmed up to me after I dealt with the bullies. They crowded around me during recess, offered to help with homework, and brought me snacks. I declined, of course, but stayed polite without letting anyone get too close. I needed them to accept me as a loner. My plan depended on it.

I watched Mr. Lee walk into the classroom. A sudden summer shower had caught him during lunch, brief but heavy, leaving the school grounds steaming under the returning sun. His copper-brown curls had sprung into extra-tight, damp curls, sticking up in soft, chaotic tufts. I watched, mesmerized, as he removed his round glasses and wiped the lenses on the hem of his stiff-collared grey shirt. He slipped them back on, then smiled at the class and softly clapped his hands for everyone to settle down. 

My heart gave a painful, unexpected twist. 

Why do I suddenly want to covet that smile all to myself?

I shook my head physically, dispelling the thought. 

Focus, man. Win his trust. Bug him. Listen in to what he’s up to in his apartment. Catch him in the act.

He turned his back to us, chalk clicking rapidly as he scribbled equations across the blackboard. I lowered my head onto my desk, but my eyes stayed fixed on the line of his shoulders and the neat slope of his back.

I had a bug hidden on me, one I'd carried for weeks, waiting for the right opportunity. It was military-grade, no larger than a fingernail, with a pinhole camera, and wafer-thin magnetic backing designed to cling beneath clothing, inside a bag, or against any metal surface. Small enough to disappear into a fold of fabric. Sensitive enough to pick up a quiet conversation from several feet away.

And, as far as I knew, impossible to spot without knowing exactly what you were looking for.

When the bell finally rang, he hurriedly gathered his things, eager to escape. But I was faster. I slung my backpack over one shoulder and closed the distance between us in the hallway before he could go far.

"Seonsaengnim!" I called out.

He stopped so abruptly he nearly dropped his stack of books. He turned, pulling them defensively over his chest, hugging them like a shield. " Ji-ho …?"

 "When can you tutor me again?" I asked, falling into step beside him as we continued down the corridor.

"Er... I'm not sure," he stammered, keeping his eyes fixed ahead. "I'm fully booked this week."

Liar.

I knew his schedule. He only tutored three students. Two Grade 7 students together on Tuesday evenings, and one Grade 9 student on Thursdays.

There was plenty of room in his schedule.

He was avoiding me.

 "Oh," I said, forcing disappointment into my voice. "I have a question about today’s lesson."

"I'm quite busy now. I have to score some scripts," he supplied quickly, turning the corner toward the admin wing.  

"I’ll be quick, seonsaengnim." 

He hesitated, but his pace slowed. His hand rose to adjust his spectacles, a nervous tell I'd catalogued weeks ago, along with the quick lick of his lower lip whenever he was uncomfortable.

His eyes flicked over me.

Not just my face.

My clenched jaw. The stubborn set of my shoulders. The way I was already walking beside him as if his answer didn't matter.

He knew I wasn't going to take no for an answer today.

He sighed.

"Okay. Come along, then." 

He led me into the gyomusil, the main teachers' office. It was a cramped, functional room with rows of individual desks packed closely together, each buried beneath lesson plans, textbooks, stationery, and stacks of marked papers. The air smelled of instant coffee and old paper. Two other teachers sat at their desks, marking scripts with red pens. The presence of his colleagues seemed to make Mr. Lee relax a fraction, afterall, there was safety in numbers. 

I suddenly felt like a stalker watching the tension visibly ease from his shoulders. 

He set his worn, olive-green canvas tote bag on the desk next to him and sat down. "Okay. Let me see."

I proceeded to drop my backpack on the floor, grabbing my flask- I’d need that later- then pulled out my notebook, which was a deliberate mess of crossed-out equations and smudged graphite. I slid it onto his desk and pointed to a convoluted calculus problem. 

“This one has me confused,” I said, screwing up my face.

 As he leaned in, his brow furrowed in concentration, a beat, then he began to explain the chain rule.  

While his eyes were on the paper and his voice filled my ears, my hands moved beneath the desk. 

From my sleeve, I slid out the device. As Hyun-woo tapped his pen against a specific variable in my notebook, I casually set my silver metal water bottle on the edge of his desk.

“The function is...,” he continued, his tone a little breathless, trying so hard to hide the lingering tension between us behind calculus. “...in differentiation, you don’t just want to know the average speed over an hour; you want to know how fast it's going at the exact split-second it…”

I subtly nudged the flask, tipping it over toward him with the lid slightly loose.

His eyes instinctively followed the movement, his hands flying out to catch the falling bottle. Capitalizing on the split-second chaos, I grabbed his bag, feigning a panicked attempt to save it from an imminent water disaster. With a fluid, practiced motion born of years in the field, I slipped one hand inside the unzipped main compartment and pressed the magnetic bug firmly onto the metal interior frame of the side pocket, securing the invisible camera on the outside. It blended perfectly into the dark seam, completely undetectable to the naked eye.

Mission complete.

“Mianhae,” I apologized, dropping my voice into that tone of gruff, teenage awkwardness as I carefully set his bag back down exactly where it had been.

He steadied my bottle and let out a small, relieved sigh. 

“That's okay,” he answered, offering a soft, surprisingly resilient smile. “No harm done. Now, where were we? Yes... you want to calculate the exact split-second it passes the marker…”

Instead of pulling back, I leaned in just a fraction closer, basking in the quiet warmth of his voice. I shamelessly let my stomach run wild with butterflies. 

What was I doing?

It was a dangerous, unprofessional distraction. I was supposed to be gathering evidence to figure out if this man was a predator, not memorizing the exact, honey-brown shade of his irises under the harsh fluorescent lights.

"Oh!" I suddenly exclaimed, faking a brilliant breakthrough to break my own trance. "I get it now. Thank you, Seonsaengnim."

Hyun-woo blinked, looking up from the notebook. He seemed genuinely surprised, and then visibly relieved that I hadn’t done anything inappropriate, like lean in too close or drop another heavy, double-meaning comment during our exchange. 

The hyper-vigilance in his face melted away. He actually smiled. 

“That’s good… see? You’re getting better at this, Ji-ho-ah.”

"No iced barley tea today, Seonsaengnim?" I asked softly, picking up and taking a slow swig from my silver flask.

At the mention of his drink, his gaze clouded with sudden, acute embarrassment, and a faint, telltale blush bloomed along his cheekbones. “No… I... I forgot it at home today.”

To that, I smiled innocently and gave him a polite, perfect fifteen-degree bow, the textbook definition of a respectful student showing gratitude to his elder.

"Gamsahamnida, seonsaengnim. I understand the lesson now."

Hearing and seeing me respond with such formal honorifics instead of my usual dismissive attitude and smart remarks made him do a double take. He smiled again.

It was soft. Warm. Completely unguarded beneath the faintest blush.

He really had no idea how dangerous a smile like that was to someone like me.

Then with a sigh, Mr Lee rubbed the back of his neck, looking almost apologetic, maybe for having handed down that brutal trash-sorting penalty the other day and avoiding me for weeks. 

"Look," he said softly, his voice taking on a gentle, encouraging tone. "If you get a perfect score on next week's mock quiz, I'll find you a private tutorial slot. And..." He hesitated, smiling slightly. "I'll get you a small reward. How does that sound?"

A reward? Interesting.

It was harmless on the surface. But I filed it away with everything else—every interaction was data. That was the only reason the moment mattered.

It certainly wasn't because the anticipation of a reward from him sent a sudden, unwanted spike of excitement straight to my gut.

My mind immediately pivoted, analyzing the trap. Was he genuinely just a sweet, hardworking educator trying to encourage a struggling, delinquent athlete? Or was this subtle grooming—the exact, calculated mechanism he used to reel vulnerable boys in?

There had to be more to this. The thought sent a sharp, thrilling charge through my pulse, a dangerous reaction I fought to suppress.

I bit the inside of my cheek hard to crush the smile threatening to break across my face.

My cover demanded a sullen, uncooperative teenager, not an eager puppy begging for a prize. I let my posture slouch again, dragging myself back into the safety of my character.

"Okay, Seonsaengnim," I muttered, ducking my head to hide my face as I swung my backpack over one shoulder. "I'll study."

"Good," he muttered. He lowered his eyes to the stack of papers on his desk and adjusted his glasses.

Our meeting was over.

I turned and walked out of the staff room.

The hallway was almost empty.

The cleaning staff was already sweeping the corridors while a few students finished their club activities outside. Somewhere in the distance, the chime of the end-of-day school bell echoed through the mountains.

Tonight, I'd start a deeper level of surveillance.

I'd look closer this time.

Two months from afar had given me nothing.

No suspicious visitors after school hours.

No late-night disappearances to hook up with minors.

No signing into online children's games to prey.

Nothing.

Just one young man who worked too hard, stayed back too late, and smiled too easily.

I needed proof.

Because if Kim Min-jae had lied... then I'd spent thousands of dollars and built an entire operation around ruining an innocent man's life.

For the first time since taking the case...

Part of me hoped I wouldn't find anything at all.

-------------------------------------------------

That evening, the rain returned, drumming against my bedroom window. I sat in the dark, the glow of my laptop washing over my face as I opened the hidden camera feed.

The video loaded first, then the audio crackled through my headphones.

I froze.

His breathing—labored.

I leaned closer to the screen, waiting for the image to sharpen. Then I saw what was happening.

Nothing could have prepared me for it.