The air in the Advanced Programming Lab was thick with the hum of thirty high-end workstations and the sterile, ozone scent of hard-working cooling fans. It was a sound I usually found comforting—a predictable, mechanical drone that drowned out the erratic noise of the outside world. But today, the silence in the room felt different. It was charged.
Ever since the morning lecture, when Danoh's eyes had locked onto my bruised knuckles and she'd offered me that small, knowing smile, the atmosphere between us had shifted. It was no longer a one-sided observation. It was a shared frequency.
"Everyone, eyes front for a moment," Professor Choi announced, his voice echoing off the sound-dampened walls.
I sat at my terminal, my spine straight, my hands folded over my lap to hide the slight discoloration of my skin. Beside me, Danoh was pulling her hair back into a loose ponytail, a habit I knew she did when she was trying to switch into 'study mode.'
"As you know, the CSE curriculum at SNU moves fast," the professor continued. "To ensure you don't drown in your first lab, I've brought in a teaching assistant. He's the pride of our department—top of his class for three consecutive years and a recipient of the Presidential Science Scholarship."
The heavy lab door swung open. A tall student walked in, moving with an easy, fluid grace that suggested he was entirely comfortable in his own skin. He wasn't wearing a baggy department hoodie like the rest of us; he wore a crisp, ironed white shirt with the sleeves rolled up to his elbows and dark slacks.
"This is Shin Sunho," the professor said.
Sunho stepped forward and bowed—a perfect, forty-five-degree bow that radiated both humility and confidence. "Hello, everyone. I'm Shin Sunho. I'm here to make sure your code compiles and your spirits don't break. Please, call me Sunho-sunbae. My door is always open."
His voice was like velvet—deep, calm, and incredibly polite. As he walked through the aisles, he didn't just look at our screens; he made brief, warm eye contact with everyone. He was the quintessential Sunbae (senior)—the kind of person Korean parents used as a benchmark for their own children.
"Alright, begin the exercise. Implement the recursive sorting algorithm I've put on the board. You have ninety minutes."
I turned to my screen. Code was my first language. To me, C++ wasn't just a programming language; it was a way to impose order on chaos. I began to type, the rhythmic clack-clack-clack of the mechanical keyboard acting as a heartbeat. I lost myself in the logic, my fingers flying across the keys as I built the structure of the program.
A shadow fell over my desk.
"Impressive," a voice murmured.
I looked up. Sunho-sunbae was leaning over my shoulder, his eyes scanning my lines of code with practiced speed. He didn't look at me with the competitive jealousy I often felt from other top students. Instead, he looked at me with genuine appreciation.
"Your memory management is incredibly clean for a freshman, Hanbin-ah," he said, using my name with a friendly suffix that felt earned rather than forced. "Professor Choi was right. You're the one to watch this year. Keep up that level of precision."
He patted my shoulder—a light, encouraging touch—and moved on. I felt a rare spark of professional pride. In the hierarchy of a Korean university, praise from a high-ranking Sunbae was the highest currency you could receive.
But my attention didn't stay on my code for long. My internal compass was still fixed to my right.
Danoh was struggling. I could tell by the way she was biting her lower lip, her eyebrows knit together in a tight line of frustration. She kept erasing lines of code, her cursor blinking mockingly at her. The 'Ice Prince' in me wanted to stay silent, to let her figure it out, but the 'Shadow' in me—the one who had bruised his knuckles for her—couldn't stand seeing her distressed.
Sunho-sunbae reached her desk next. He crouched down so he was at eye level with her, a gesture of politeness that didn't go unnoticed by the other girls in the room.
"Hard time with the base case, Danoh-ssi?" he asked softly.
"I... I keep getting a stack overflow error," she whispered, her face flushing pink. "I'm sorry, Sunbae. I'll try harder."
"Don't apologize for a bug. Bugs are just lessons in disguise," Sunho said with a warm smile. He looked over at me, then back at her. "Actually, you're sitting next to the best debugger in the room. Hanbin-ah?"
I looked up, my pulse skipping.
Sunho gestured toward Danoh's screen. "Why don't you help her out? Sometimes a peer's explanation is better than a senior's lecture. Junior, help her too. She's got the logic; she just needs a nudge on the syntax."
I swallowed. "Okay."
I shifted my chair closer to hers. The scent of her strawberry shampoo, faint and sweet, drifted over to me again. It was a dangerous distraction.
"Here," I said, my voice lower than usual. I pointed at the fifth line of her function. "Your recursive call doesn't have a stopping condition. It'll loop forever."
"Oh!" She leaned in closer to see where I was pointing. Our shoulders weren't touching, but the proximity was enough to make the air feel thick. "I see it now. I'm so stupid."
"You're not," I said firmly, looking her in the eye. "It's a common mistake."
"Thanks, Hanbin," she murmured, her voice shy and gentle. The way she used my name without the 'Ssi'—as we had agreed—sent a thrill of heat through my chest.
"Ahem! Hanbin-ssi? I think I have a bug too!"
A voice chirped from the desk behind us. I turned to see Jeong Jisoo, a girl known for having the loudest laugh in the freshman class. She was leaning forward, her chin resting on her hand, her eyes wide and fluttering in a way that was clearly intentional.
"I'm totally lost," Jisoo said, pouting. "Can you look at mine? Please?"
I felt Danoh stiffen beside me. I looked at Jisoo's screen. Her code was a mess, but it wasn't a 'lost' mess; it was the kind of mess you make when you aren't paying attention.
"Sunho-sunbae is right there," I said coldly.
"But Sunbae is busy with the Professor," Jisoo giggled, reaching out to lighty touch my forearm. "And you're so much closer. Help a girl out?"
I pulled my arm back as if I'd been burned. My focus remained entirely on Danoh. I could see her out of the corner of my eye—she was staring at her keyboard, her movements becoming stiff. She was retreating into her shell.
"The logic is in the textbook, page forty-two," I told Jisoo, not looking at her. "I need to finish my own work."
"So cold!" Jisoo whispered, though she didn't sound truly offended; she seemed amused by the challenge.
I turned back to Danoh. She was typing again, but her movements were tentative. I leaned in, ignoring the rest of the room.
"Don't listen to the noise," I whispered, so low only she could hear. "Just focus on the logic. You're doing fine."
Danoh looked at me, her gaze lingering on my face. The shyness was there, but beneath it was a growing sense of trust. She nodded, a small, genuine smile tugging at the corners of her mouth.
Throughout the rest of the lab, Sunho-sunbae moved like a diplomat, offering help and praise with an almost saintly patience. He was perfect. Too perfect. While the rest of the department saw a mentor, I saw a variable I couldn't yet account for in my system. He was polite to Danoh—perhaps a little too polite.
When the lab ended, Sunho stood at the front. "Great work today, juniors. Hanbin, Danoh—keep working together. Collaboration is the key to engineering."
As we packed our bags, the room was a flurry of activity. Jisoo tried to catch my eye again, but I was already standing, waiting for Danoh.
"Are you going to the library?" I asked her.
"I think I need to," she said, glancing at her bandaged leg. "I have a lot of catching up to do."
"I'll go with you," I said.
We walked out of the lab together. As we passed Sunho-sunbae, he gave us a small, encouraging wave. I didn't wave back. I just placed myself between Danoh and the crowded hallway, my hand hovering near the small of her back, not touching, but close enough to let the world know she was under my protection.
The "Shadow" didn't need praise from a senior. I didn't need to be the "best student" in the eyes of the Professor. I only needed the girl beside me to feel safe enough to keep smiling.
And as we stepped into the golden afternoon light of the campus, I knew that the variable of Shin Sunho was something I would be watching very, very closely.