Gangneung's dawn rolled in heavy with fog, smothering the glass windows of Haesin University Hospital with a pale breath that blurred the city outside. The corridors buzzed quietly, footsteps of nurses layered with distant monitors beeping steady rhythms. It was another morning where nothing felt new, but everything felt like it could tip into something else with the wrong glance.
Seo Yoon stood in the surgical prep room, her hands moving mechanically as she tied her hair back, slipped her arms into her white coat, and checked the penlight in her pocket. Her reflection in the metal cabinet was calm, but her eyes betrayed the turbulence layered beneath.
The folded paper inside her coat weighed heavier than any scalpel she had ever held.
---
The patient list was routine that morning, but room 308 made her pause. Han Min Gyu was admitted for a stent procedure scheduled later in the week. He was loud when he spoke, making nurses shrink back, laughing too hard at his own jokes, eyes scanning every woman in the room with the same familiarity he used to mask what he was.
She passed by his door, eyes glancing in. He was talking to someone on the phone, bragging about the nurse who had checked his vitals, calling her "sweet, shy, perfect."
Seo Yoon kept walking, the paper in her pocket crinkling with every step.
---
Detective Hyun Woo had not slept well. Files were scattered across his coffee table as he sipped instant coffee that had long gone cold. Three deaths, one pattern, and a single thread: each victim had spent time in Haesin or affiliated hospitals in the last decade.
He circled the hospital's name in red, his pen pausing. A memory flickered: the quiet doctor with dark eyes he had run into twice now. Seo Yoon.
It wasn't a suspicion. It was curiosity. But curiosity was the mother of realization.
He closed the file, grabbing his coat.
---
At the hospital, he walked past the reception, badge flashed briefly, asking for records of visitors connected to Nam Tae Jin, Park Jun Seok, and Shin Kyung Ho. He was met with confusion, polite nods, and promises to check.
As he turned to leave, he saw her.
Seo Yoon, standing by the stairwell, her coat draped neatly over her arm as she spoke to a young nurse, a soft smile on her lips that did not reach her eyes.
Their eyes met briefly. She nodded once, acknowledging him, and turned away.
He couldn't tell why, but the way she moved made him think of someone balancing glass in their hands.
---
That evening, the fog turned to rain, spattering against the windows as the city lights flickered on. Seo Yoon sat in the empty cafeteria with a cup of barley tea, her phone on silent, her eyes lost in the storm outside.
Her hand slipped into her pocket, pulling out the folded report on Han Min Gyu. She opened it carefully, smoothing out the creases, reading the words she had memorized. Dismissed. Withdrawn. Untouched.
A quiet rage boiled beneath the calm.
She closed her eyes, breathing in, and let it settle into something sharp and quiet.
---
In her small apartment that night, she opened her wardrobe and reached for the bottom drawer, pulling out a black canvas bag. Inside was a small kit, tools clean and organized: gloves, medical tape, vials, syringes, and a single scalpel she had kept from her residency.
She touched the handle with gloved fingers, feeling the weight.
On the bedside table, a photo frame lay facedown. She picked it up, staring at the image of two young girls, identical, standing beside a tired woman with kind eyes. The girl beside Seo Yoon had her head tilted, a half-smile on her lips, eyes that mirrored her own.
"You promised," she whispered.
In the silence, she felt the presence beside her, a warmth that was not entirely there but not entirely gone.
---
Han Min Gyu would be moved for pre-op observation in two days. She knew the schedule, the nurses on rotation, and the cameras that flickered on and off during power checks.
She closed the kit and placed it back into the drawer, locking it carefully.
The rain outside eased into a gentle drizzle, tapping on the balcony railing softly, like quiet applause.
Seo Yoon lay down on her bed, eyes open, listening to the rain until sleep took her.
---
At dawn, she woke up, showered, dressed, and stood in front of the mirror, tying her hair back as the steam from her tea curled around her reflection.
She slipped the report into her coat, placed her phone in her pocket, and left her apartment.
In the hallway, she paused, looking back at the closed door.
"I'll keep us safe," she whispered.
The presence behind her was silent, but she felt the air shift, like an agreement.
---
At the hospital, as she checked the charts, she passed by Hyun Woo in the corridor. He was talking to a nurse, showing her a photo on his phone, nodding as she spoke nervously.
Their eyes met again.
"Doctor," he said, stepping closer.
"Detective," she replied calmly.
"Strange, running into you so often."
"I work here. You're the stranger," she said softly, a ghost of a smile on her lips.
He chuckled, rubbing the back of his neck. "Fair point."
"Is there something you need?" she asked.
He hesitated. "Just… be careful, okay?"
Her eyes flickered, searching his face. "You too."
She turned and walked away, each step measured, her heart steady.
---
In Room 308, Han Min Gyu was asleep, monitors beeping steadily beside him.
Seo Yoon stood at the door, watching, her face unreadable.
In two days, the line would be crossed.
And no one would see it coming.
---